Anonymous user
Middle three digits: Difference between revisions
m
→{{header|Elena}}
m (→{{header|Ruby}}: Correct mang tag.) |
imported>Arakov |
||
| (327 intermediate revisions by more than 100 users not shown) | |||
Line 1:
{{task}}
;Task:
Write a function/procedure/subroutine that is called with an integer value and returns the middle three digits of the integer if possible or a clear indication of an error if this is not possible.
Note: The order of the middle digits should be preserved.
Your function should be tested with the following values; the first line should return valid answers, those of the second line should return clear indications of an error:
<pre>
123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345
1, 2, -1, -10, 2002, -2002, 0
</pre>
Show your output on this page.
<br><br>
=={{header|
{{trans|Python}}
<syntaxhighlight lang="11l">F middle_three_digits(i)
V s = String(abs(i))
assert(s.len >= 3 & s.len % 2 == 1, ‘Need odd and >= 3 digits’)
R s[s.len I/ 2 - 1 .+ 3]
V passing = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345]
V failing = [1, 2, -1, -10, 2002, -2002, 0]
L(x) passing [+] failing
X.try
V answer = middle_three_digits(x)
print(‘middle_three_digits(#.) returned: #.’.format(x, answer))
X.catch AssertionError error
print(‘middle_three_digits(#.) returned error: ’.format(x)‘’String(error))</syntaxhighlight>
{{out}}
<pre>
middle_three_digits(123) returned: 123
middle_three_digits(12345) returned: 234
middle_three_digits(1234567) returned: 345
middle_three_digits(987654321) returned: 654
middle_three_digits(10001) returned: 000
middle_three_digits(-10001) returned: 000
middle_three_digits(-123) returned: 123
middle_three_digits(-100) returned: 100
middle_three_digits(100) returned: 100
middle_three_digits(-12345) returned: 234
middle_three_digits(1) returned error: Need odd and >= 3 digits
middle_three_digits(2) returned error: Need odd and >= 3 digits
middle_three_digits(-1) returned error: Need odd and >= 3 digits
middle_three_digits(-10) returned error: Need odd and >= 3 digits
middle_three_digits(2002) returned error: Need odd and >= 3 digits
middle_three_digits(-2002) returned error: Need odd and >= 3 digits
middle_three_digits(0) returned error: Need odd and >= 3 digits
</pre>
=={{header|Action!}}==
{{libheader|Action! Tool Kit}}
{{libheader|Action! Real Math}}
<syntaxhighlight lang="action!">INCLUDE "H6:REALMATH.ACT"
INCLUDE "D2:PRINTF.ACT" ;from the Action! Tool Kit
PROC MiddleThreeDigits(REAL POINTER n CHAR ARRAY res)
REAL r
CHAR ARRAY s(15)
BYTE i
RealAbs(n,r)
StrR(r,s)
i=s(0)
IF i<3 OR (i&1)=0 THEN
res(0)=0
ELSE
i==RSH 1
SCopyS(res,s,i,i+2)
FI
RETURN
PROC Test(CHAR ARRAY s)
REAL n
CHAR ARRAY res(4)
ValR(s,n)
MiddleThreeDigits(n,res)
IF res(0) THEN
PrintF("%9S -> %S%E",s,res)
ELSE
PrintF("%9S -> error!%E",s)
FI
RETURN
PROC Main()
Put(125) PutE() ;clear the screen
Test("123") Test("12345")
Test("1234567") Test("987654321")
Test("10001") Test("-10001")
Test("-123") Test("-100")
Test("100") Test("-12345")
Test("1") Test("2")
Test("-1") Test("-10")
Test("2002") Test("-2002")
Test("0")
RETURN</syntaxhighlight>
{{out}}
[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Middle_three_digits.png Screenshot from Atari 8-bit computer]
<pre>
123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> error!
2 -> error!
-1 -> error!
-10 -> error!
2002 -> error!
-2002 -> error!
0 -> error!
</pre>
=={{header|Ada}}==
<syntaxhighlight lang="ada">with Ada.Text_IO;
procedure Middle_Three_Digits is
Impossible: exception;
function Middle_String(I: Integer; Middle_Size: Positive) return String is
S: constant String := Integer'Image(I);
First: Natural := S'First;
Full_Size, Border: Natural;
begin
while S(First) not in '0' .. '9' loop -- skip leading blanks and minus
First := First + 1;
end loop;
Full_Size := S'Last-First+1;
if (Full_Size < Middle_Size) or (Full_Size mod 2 = 0) then
raise Impossible;
else
Border := (Full_Size - Middle_Size)/2;
return S(First+Border .. First+Border+Middle_Size-1);
end if;
end Middle_String;
Inputs: array(Positive range <>) of Integer :=
(123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345,
1, 2, -1, -10, 2002, -2002, 0);
Error_Message: constant String := "number of digits must be >= 3 and odd";
package IIO is new Ada.Text_IO.Integer_IO(Integer);
begin
for I in Inputs'Range loop
IIO.Put(Inputs(I), Width => 9);
Ada.Text_IO.Put(": ");
begin
Ada.Text_IO.Put(Middle_String(Inputs(I), 3));
exception
when Impossible => Ada.Text_IO.Put("****" & Error_Message & "****");
end;
Ada.Text_IO.New_Line;
end loop;
end Middle_Three_Digits;</syntaxhighlight>
{{out}}
<pre> 123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: ****number of digits must be >= 3 and odd****
2: ****number of digits must be >= 3 and odd****
-1: ****number of digits must be >= 3 and odd****
-10: ****number of digits must be >= 3 and odd****
2002: ****number of digits must be >= 3 and odd****
-2002: ****number of digits must be >= 3 and odd****
0: ****number of digits must be >= 3 and odd****</pre>
=={{header|Aime}}==
<syntaxhighlight lang="aime">void
m3(integer i)
{
text s;
if (s[0] == '-') {
s = delete(s, 0);
}
if (~s < 3) {
v_integer(i);
v_text(" has not enough digits\n");
} elif (~s & 1) {
o_form("/w9/: ~\n", i, cut(s, ~s - 3 >> 1, 3));
} else {
v_integer(i);
v_text(" has an even number of digits\n");
}
}
void
middle_3(...)
{
integer i;
i = 0;
while (i < count()) {
m3($i);
i += 1;
}
}
integer
main(void)
{
middle_3(123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100,
-12345, 1, 2, -1, -10, 2002, -2002, 0);
return 0;
}</syntaxhighlight>
{{out}}
<pre> 123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1 has not enough digits
2 has not enough digits
-1 has not enough digits
-10 has not enough digits
2002 has an even number of digits
-2002 has an even number of digits
0 has not enough digits</pre>
=={{header|ALGOL 68}}==
{{works with|ALGOL 68G|Any - tested with release 2.6.win32}}
<syntaxhighlight lang="algol68"># we define a UNION MODE so that our middle 3 digits PROC can #
# return either an integer on success or a error message if #
# the middle 3 digits couldn't be extracted #
MODE EINT = UNION( INT # success value #, STRING # error message # );
# PROC to return the middle 3 digits of an integer. #
# if this is not possible, an error message is returned #
# instead #
PROC middle 3 digits = ( INT number ) EINT:
BEGIN
# convert the absolute value of the number to a string with the #
# minumum possible number characters #
STRING digits = whole( ABS number, 0 );
INT len = UPB digits;
IF len < 3
THEN
# number has less than 3 digits #
# return an error message #
"number must have at least three digits"
ELIF ( len MOD 2 ) = 0
THEN
# the number has an even number of digits #
# return an error message #
"number must have an odd number of digits"
ELSE
# the number is suitable for extraction of the middle 3 digits #
INT first digit pos = 1 + ( ( len - 3 ) OVER 2 );
# the result is the integer value of the three digits #
( ( ( ABS digits[ first digit pos ] - ABS "0" ) * 100 )
+ ( ( ABS digits[ first digit pos + 1 ] - ABS "0" ) * 10 )
+ ( ( ABS digits[ first digit pos + 2 ] - ABS "0" ) )
)
FI
END; # middle 3 digits #
main: (
# test the middle 3 digits PROC #
[]INT test values = ( 123, 12345, 1234567, 987654321
, 10001, -10001, -123, -100
, 100, -12345
# the following values should fail #
, 1, 2, -1, -10, 2002, -2002, 0
);
FOR test number FROM LWB test values TO UPB test values
DO
CASE middle 3 digits( test values[ test number ] )
IN
( INT success value ): # got the middle 3 digits #
printf( ( $ 11z-d, " : ", 3d $
, test values[ test number ]
, success value
)
)
,
( STRING error message ): # got an error message #
printf( ( $ 11z-d, " : ", n( UPB error message )a $
, test values[ test number ]
, error message
)
)
ESAC;
print( ( newline ) )
OD
)</syntaxhighlight>
{{out}}
<pre>
123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : number must have at least three digits
2 : number must have at least three digits
-1 : number must have at least three digits
-10 : number must have at least three digits
2002 : number must have an odd number of digits
-2002 : number must have an odd number of digits
0 : number must have at least three digits
</pre>
=={{header|ALGOL W}}==
<syntaxhighlight lang="algolw">begin
% record structure that will be used to return the middle 3 digits of a number %
% if the middle three digits can't be determined, isOk will be false and message %
% will contain an error message %
% if the middle 3 digts can be determined, middle3 will contain the middle 3 %
% digits and isOk will be true %
record MiddleThreeDigits ( integer middle3; logical isOk; string(80) message );
% finds the middle3 digits of a number or describes why they can't be found %
reference(MiddleThreeDigits) procedure findMiddleThreeDigits ( integer value number ) ;
begin
integer n, digitCount, d;
n := abs( number );
% count the number of digits the number has %
digitCount := if n = 0 then 1 else 0;
d := n;
while d > 0 do begin
digitCount := digitCount + 1;
d := d div 10
end while_d_gt_0 ;
if digitCount < 3 then MiddleThreeDigits( 0, false, "Number must have at least 3 digits" )
else if not odd( digitCount ) then MiddleThreeDigits( 0, false, "Number must have an odd number of digits" )
else begin
% can find the middle three digits %
integer m3;
m3 := n;
for d := 1 until ( digitCount - 3 ) div 2 do m3 := m3 div 10;
MiddleThreeDigits( m3 rem 1000, true, "" )
end
end findMiddleThreeDigits ;
% test the findMiddleThreeDigits procedure %
for n := 123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0 do begin
reference(MiddleThreeDigits) m3;
i_w := 10; s_w := 0; % set output formating %
m3 := findMiddleThreeDigits( n );
write( n, ": " );
if not isOk(m3) then writeon( message(m3) )
else begin
% as we return the middle three digits as an integer, we must manually 0 pad %
if middle3(m3) < 100 then writeon( "0" );
if middle3(m3) < 10 then writeon( "0" );
writeon( i_w := 1, middle3(m3) )
end
end for_n
end.</syntaxhighlight>
{{out}}
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: Number must have at least 3 digits
2: Number must have at least 3 digits
-1: Number must have at least 3 digits
-10: Number must have at least 3 digits
2002: Number must have an odd number of digits
-2002: Number must have an odd number of digits
0: Number must have at least 3 digits
</pre>
=={{header|Amazing Hopper}}==
<p>VERSION 1:</p>
<syntaxhighlight lang="c">
#include <basico.h>
algoritmo
n=0, c=""
temp = 0, candidatos={}
'123, 12345, 1234567, 987654321, 10001, -10001,-123'
'-100, 100, -12345,1, 2, -1, -10, 2002, -2002, 0'
enlistar en 'candidatos'
decimales '0'
#basic{
temp = string(candidatos * sign(candidatos))
n = len( temp )
c = replicate (temp, n>=3 && not(is even(n)))
toksep(NL)
print (cat( lpad(" ",11,string(candidatos)), cat(" : ", copy( 3, (n/2-1), c ))),NL)
}
terminar
</syntaxhighlight>
{{out}}
<pre>
123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 :
2 :
-1 :
-10 :
2002 :
-2002 :
0 :
</pre>
<p>VERSION 2:</p>
<syntaxhighlight lang="c">
#include <basico.h>
algoritmo
n=0, c="",
temp = 0, candidatos={}
'123, 12345, 1234567, 987654321, 10001, -10001,-123'
'-100, 100, -12345,1, 2, -1, -10, 2002, -2002, 0'
enlistar en 'candidatos'
decimales '0'
tomar 'candidatos', quitar el signo
convertir a cadena ---retener---, obtener largo, mover a 'n',
guardar en 'temp'
guardar ' replicar ( temp, #(n>=3 && not(is even(n))))' en 'c'
token.separador(NL)
justificar derecha(11,#(string(candidatos))), " : ", concatenar esto
#( copy( 3, (n/2-1), c ) ), unir esto
luego imprime
terminar
</syntaxhighlight>
{{out}}
<pre>
123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 :
2 :
-1 :
-10 :
2002 :
-2002 :
0 :
</pre>
<p>VERSION 3:</p>
<syntaxhighlight lang="c">
#include <basico.h>
algoritmo
n=0, c="", m=0,
candidatos={}
'123, 12345, 1234567, 987654321, 10001, -10001,-123'
'-100, 100, -12345,1, 2, -1, -10, 2002, -2002, 0'
enlistar en 'candidatos'
decimales '0'
para cada elemento (v,candidatos,17)
tomar'v' ---copiar en 'm'---, quitar el signo
guardar en 'v'
#(len( c:=(string(v)) ) ), mover a 'n'
"Num: ",justificar derecha(10,#(string(m))),"(",n,")\t"
si ' #( n>=3 && not(is even(n))) '
" puede ser procesado : "
tomar si ( #(n==3), 'c', #( copy( 3, (n/2-1), c )) ), NL
sino
"no puede ser procesado\n"
fin si
luego imprime
siguiente
terminar
</syntaxhighlight>
{{out}}
<pre>
Num: 123(3) puede ser procesado : 123
Num: 12345(5) puede ser procesado : 234
Num: 1234567(7) puede ser procesado : 345
Num: 987654321(9) puede ser procesado : 654
Num: 10001(5) puede ser procesado : 000
Num: -10001(5) puede ser procesado : 000
Num: -123(3) puede ser procesado : 123
Num: -100(3) puede ser procesado : 100
Num: 100(3) puede ser procesado : 100
Num: -12345(5) puede ser procesado : 234
Num: 1(1) no puede ser procesado
Num: 2(1) no puede ser procesado
Num: -1(1) no puede ser procesado
Num: -10(2) no puede ser procesado
Num: 2002(4) no puede ser procesado
Num: -2002(4) no puede ser procesado
Num: 0(1) no puede ser procesado
</pre>
=={{header|AppleScript}}==
===Procedural===
987654321 is too large to be represented as an AppleScript integer, so "integer value" is taken here to refer to the numeric value rather than to the language class. AppleScript automatically coerces numeric text and single-item lists to appropriate number classes where necessary and possible, so these are acceptable as parameters too.
<syntaxhighlight lang="applescript">on middle3Digits(n)
try
n as number -- Errors if n isn't a number or coercible thereto.
set s to n as text -- Keep for the ouput string.
if (n mod 1 is not 0) then error (s & " isn't an integer value.")
if (n < 0) then set n to -n
if (n < 100) then error (s & " has fewer than three digits.")
-- Coercing large numbers to text may result in E notation, so extract the digit values individually.
set theDigits to {}
repeat until (n = 0)
set beginning of theDigits to n mod 10 as integer
set n to n div 10
end repeat
set c to (count theDigits)
if (c mod 2 is 0) then error (s & " has an even number of digits.")
on error errMsg
return "middle3Digits handler got an error: " & errMsg
end try
set i to (c - 3) div 2 + 1
set {x, y, z} to items i thru (i + 2) of theDigits
return "The middle three digits of " & s & " are " & ((x as text) & y & z & ".")
end middle3Digits
-- Test code:
set testNumbers to {123, 12345, 1234567, "987654321", "987654321" as number, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0}
set output to {}
repeat with thisNumber in testNumbers
set end of output to middle3Digits(thisNumber)
end repeat
set astid to AppleScript's text item delimiters
set AppleScript's text item delimiters to linefeed
set output to output as text
set AppleScript's text item delimiters to astid
return output</syntaxhighlight>
{{output}}
<syntaxhighlight lang="applescript">"The middle three digits of 123 are 123.
The middle three digits of 12345 are 234.
The middle three digits of 1234567 are 345.
The middle three digits of 987654321 are 654.
The middle three digits of 9.87654321E+8 are 654.
The middle three digits of 10001 are 000.
The middle three digits of -10001 are 000.
The middle three digits of -123 are 123.
The middle three digits of -100 are 100.
The middle three digits of 100 are 100.
The middle three digits of -12345 are 234.
middle3Digits handler got an error: 1 has fewer than three digits.
middle3Digits handler got an error: 2 has fewer than three digits.
middle3Digits handler got an error: -1 has fewer than three digits.
middle3Digits handler got an error: -10 has fewer than three digits.
middle3Digits handler got an error: 2002 has an even number of digits.
middle3Digits handler got an error: -2002 has an even number of digits.
middle3Digits handler got an error: 0 has fewer than three digits."</syntaxhighlight>
===Functional===
<syntaxhighlight lang="applescript">-------------------- MID THREE DIGITS ---------------------
-- mid3digits :: Int -> Either String String
on mid3digits(n)
-- Either a message explaining why
-- no "mid 3 digits" are defined for n,
-- or the mid 3 digits themselves.
set m to abs(n)
if 100 > m then
|Left|("Less than 3 digits")
else if maxBound(1) < m then
|Left|("Out of AppleScript integer range")
else
set s to m as string
set intDigits to length of s
if even(intDigits) then
|Left|("Even digit count")
else
|Right|((items 1 thru 3 of ¬
items (1 + ((intDigits - 3) div 2)) thru -1 of s) as string)
end if
end if
end mid3digits
-------------------------- TEST ---------------------------
on run
set ints to map(readInt, splitOn(", ", ¬
"123, 12345, 1234567, 987654321, 10001, -10001, " & ¬
"-123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0"))
script showResult
on |λ|(x)
either(my bracketed, my str, x)
end |λ|
end script
fTable("Mid three digits:", str, showResult, mid3digits, ints)
end run
------------------------ GENERICS -------------------------
-- Left :: a -> Either a b
on |Left|(x)
{type:"Either", |Left|:x, |Right|:missing value}
end |Left|
-- Right :: b -> Either a b
on |Right|(x)
{type:"Either", |Left|:missing value, |Right|:x}
end |Right|
-- abs :: Num -> Num
on abs(x)
-- Absolute value.
if 0 > x then
-x
else
x
end if
end abs
-- even :: Int -> Bool
on even(x)
0 = x mod 2
end even
-- maxBound :: a -> a
on maxBound(x)
set c to class of x
if text is c then
character id 65535
else if integer is c then
(2 ^ 29 - 1)
else if real is c then
1.797693E+308
else if boolean is c then
true
end if
end maxBound
-------------------- GENERICS FOR TEST AND DISPLAY ---------------------
-- bracketed :: String -> String
on bracketed(s)
"(" & s & ")"
end bracketed
-- compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
on compose(f, g)
script
property mf : mReturn(f)
property mg : mReturn(g)
on |λ|(x)
mf's |λ|(mg's |λ|(x))
end |λ|
end script
end compose
-- either :: (a -> c) -> (b -> c) -> Either a b -> c
on either(lf, rf, e)
if missing value is |Left| of e then
tell mReturn(rf) to |λ|(|Right| of e)
else
tell mReturn(lf) to |λ|(|Left| of e)
end if
end either
-- foldl :: (a -> b -> a) -> a -> [b] -> a
on foldl(f, startValue, xs)
tell mReturn(f)
set v to startValue
set lng to length of xs
repeat with i from 1 to lng
set v to |λ|(v, item i of xs, i, xs)
end repeat
return v
end tell
end foldl
-- fTable :: String -> (a -> String) -> (b -> String) -> (a -> b) -> [a] -> String
on fTable(s, xShow, fxShow, f, xs)
set ys to map(xShow, xs)
set w to maximum(map(my |length|, ys))
script arrowed
on |λ|(a, b)
justifyRight(w, space, a) & " -> " & b
end |λ|
end script
s & linefeed & unlines(zipWith(arrowed, ¬
ys, map(compose(fxShow, f), xs)))
end fTable
-- justifyRight :: Int -> Char -> String -> String
on justifyRight(n, cFiller, strText)
if n > length of strText then
text -n thru -1 of ((replicate(n, cFiller) as text) & strText)
else
strText
end if
end justifyRight
-- length :: [a] -> Int
on |length|(xs)
set c to class of xs
if list is c or string is c then
length of xs
else
(2 ^ 29 - 1) -- (maxInt - simple proxy for non-finite)
end if
end |length|
-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
-- The list obtained by applying f
-- to each element of xs.
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map
-- maximum :: Ord a => [a] -> a
on maximum(xs)
script
on |λ|(a, b)
if a is missing value or b > a then
b
else
a
end if
end |λ|
end script
foldl(result, missing value, xs)
end maximum
-- min :: Ord a => a -> a -> a
on min(x, y)
if y < x then
y
else
x
end if
end min
-- mReturn :: First-class m => (a -> b) -> m (a -> b)
on mReturn(f)
-- 2nd class handler function lifted into 1st class script wrapper.
if script is class of f then
f
else
script
property |λ| : f
end script
end if
end mReturn
-- readInt :: String -> Int
on readInt(s)
s as integer
end readInt
-- Egyptian multiplication - progressively doubling a list, appending
-- stages of doubling to an accumulator where needed for binary
-- assembly of a target length
-- replicate :: Int -> a -> [a]
on replicate(n, a)
set out to {}
if 1 > n then return out
set dbl to {a}
repeat while (1 < n)
if 0 < (n mod 2) then set out to out & dbl
set n to (n div 2)
set dbl to (dbl & dbl)
end repeat
return out & dbl
end replicate
-- splitOn :: String -> String -> [String]
on splitOn(pat, src)
set {dlm, my text item delimiters} to ¬
{my text item delimiters, pat}
set xs to text items of src
set my text item delimiters to dlm
return xs
end splitOn
-- str :: a -> String
on str(x)
x as string
end str
-- unlines :: [String] -> String
on unlines(xs)
-- A single string formed by the intercalation
-- of a list of strings with the newline character.
set {dlm, my text item delimiters} to ¬
{my text item delimiters, linefeed}
set s to xs as text
set my text item delimiters to dlm
s
end unlines
-- zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
on zipWith(f, xs, ys)
set lng to min(length of xs, length of ys)
set lst to {}
if 1 > lng then
return {}
else
tell mReturn(f)
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, item i of ys)
end repeat
return lst
end tell
end if
end zipWith</syntaxhighlight>
{{Out}}
<pre>Mid three digits:
123 -> 123
12345 -> 234
1234567 -> 345
9.87654321E+8 -> (Out of AppleScript integer range)
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> (Less than 3 digits)
2 -> (Less than 3 digits)
-1 -> (Less than 3 digits)
-10 -> (Less than 3 digits)
2002 -> (Even digit count)
-2002 -> (Even digit count)
0 -> (Less than 3 digits)</pre>
=={{header|Arturo}}==
<syntaxhighlight lang="rebol">middleThree: function [num][
n: to :string abs num
if 3 > size n -> return "Number must have at least three digits"
if even? size n -> return "Number must have an odd number of digits"
middle: ((size n)/2)- 1
return slice n middle middle+2
]
samples: @[
123, 12345, 1234567, 987654321, 10001, neg 10001, neg 123, neg 100, 100, neg 12345,
1, 2, neg 1, neg 10, 2002, neg 2002, 0
]
loop samples 's [
print [pad to :string s 10 ":" middleThree s]
]</syntaxhighlight>
{{out}}
<pre> 123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : Number must have at least three digits
2 : Number must have at least three digits
-1 : Number must have at least three digits
-10 : Number must have at least three digits
2002 : Number must have an odd number of digits
-2002 : Number must have an odd number of digits
0 : Number must have at least three digits</pre>
=={{header|ATS}}==
<syntaxhighlight lang="ats">
(* ****** ****** *)
//
#include
"share/atspre_staload.hats"
#include
"share/HATS/atspre_staload_libats_ML.hats"
//
(* ****** ****** *)
//
extern
fun
int2digits(x: int): list0(int)
//
(* ****** ****** *)
implement
int2digits(x) =
loop(x, list0_nil) where
{
//
fun
loop
(
x: int, res: list0(int)
) : list0(int) =
if x > 0 then loop(x/10, list0_cons(x%10, res)) else res
//
} (* end of [int2digits] *)
(* ****** ****** *)
extern
fun
Middle_three_digits(x: int): void
(* ****** ****** *)
implement
Middle_three_digits
(x0) = let
//
val x1 =
(
if x0 >= 0 then x0 else ~x0
) : int
//
fun
skip
(
ds: list0(int), k: int
) : list0(int) =
if k > 0 then skip(ds.tail(), k-1) else ds
//
val ds =
int2digits(x1)
//
val n0 = length(ds)
//
in
//
if
(n0 <= 2)
then
(
println! ("Middle-three-digits(", x0, "): Too small!")
)
else
(
if
(n0 % 2 = 0)
then
(
println!
(
"Middle-three-digits(", x0, "): Even number of digits!"
)
)
else let
val ds =
skip(ds, (n0-3)/2)
val-list0_cons(d1, ds) = ds
val-list0_cons(d2, ds) = ds
val-list0_cons(d3, ds) = ds
in
println! ("Middle-three-digits(", x0, "): ", d1, d2, d3)
end // end of [else]
)
//
end // end of [Middle_three_digits]
(* ****** ****** *)
implement
main0() =
{
//
val
thePassing =
g0ofg1
(
$list{int}
(
123
, 12345
, 1234567
, 987654321
, 10001, ~10001
, ~123, ~100, 100, ~12345
)
)
val
theFailing =
g0ofg1($list{int}(1, 2, ~1, ~10, 2002, ~2002, 0))
//
val () = thePassing.foreach()(lam x => Middle_three_digits(x))
val () = theFailing.foreach()(lam x => Middle_three_digits(x))
//
} (* end of [main0] *)
(* ****** ****** *)
</syntaxhighlight>
{{out}}
<pre>Middle-three-digits(123): 123
Middle-three-digits(12345): 234
Middle-three-digits(1234567): 345
Middle-three-digits(987654321): 654
Middle-three-digits(10001): 000
Middle-three-digits(-10001): 000
Middle-three-digits(-123): 123
Middle-three-digits(-100): 100
Middle-three-digits(100): 100
Middle-three-digits(-12345): 234
Middle-three-digits(1): Too small!
Middle-three-digits(2): Too small!
Middle-three-digits(-1): Too small!
Middle-three-digits(-10): Too small!
Middle-three-digits(2002): Even number of digits!
Middle-three-digits(-2002): Even number of digits!
Middle-three-digits(0): Too small!</pre>
=={{header|AutoHotkey}}==
<syntaxhighlight lang="autohotkey">Numbers:="123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345,1,2,-1,-10,2002,-2002,0"
Loop, parse, Numbers, `,
{
if A_LoopField is not number
log := log . A_LoopField . "`t: Not a valid number`n"
else if((d:=StrLen(n:=RegExReplace(A_LoopField,"\D")))<3)
log := log . A_LoopField . "`t: Too short`n"
else if(!Mod(d,2))
log := log . A_LoopField . "`t: Not an odd number of digits`n"
else
log := log . A_LoopField . "`t: " . SubStr(n,((d-3)//2)+1,3) . "`n"
}
MsgBox % log</syntaxhighlight>
{{out}}
<pre>123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : Too short
2 : Too short
-1 : Too short
-10 : Too short
2002 : Not an odd number of digits
-2002 : Not an odd number of digits
0 : Too short</pre>
=={{header|AWK}}==
<syntaxhighlight lang="awk">#!/bin/awk -f
# use as: awk -f middle_three_digits.awk
BEGIN {
n = split("123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1 -10 2002 -2002 0", arr)
for (i=1; i<=n; i++) {
if (arr[i] !~ /^-?[0-9]+$/) {
printf("%10s : invalid input: not a number\n", arr[i])
continue
}
num = arr[i]<0 ? -arr[i]:arr[i]
len = length(num)
if (len < 3) {
printf("%10s : invalid input: too few digits\n", arr[i])
continue
}
if (len % 2 == 0) {
printf("%10s : invalid input: even number of digits\n", arr[i])
continue
}
printf("%10s : %s\n", arr[i], substr(num, len/2, 3))
}
}
</syntaxhighlight>
{{out}}
<pre>
123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : invalid input: too few digits
2 : invalid input: too few digits
-1 : invalid input: too few digits
-10 : invalid input: too few digits
2002 : invalid input: even number of digits
-2002 : invalid input: even number of digits
0 : invalid input: too few digits
</pre>
=={{header|BASIC}}==
==={{header|Applesoft BASIC}}===
<syntaxhighlight lang="applesoftbasic">100 DEF FN L(N) = LEN(STR$(INT(ABS(N))))
110 DEF FN N(N) = VAL(MID$(STR$(INT(ABS(N))),(FN L(N)-1)/2,3))
120 DEF FN EVEN(N) = INT(N/2) = N/2
130 FOR I = 1 TO 20
140 READ N
150 PRINT N":",
160 GOSUB 100"MIDDLE THREE DIGITS
170 PRINT R$
180 NEXT
190 END
200 R$ = ""
210 IF FN EVEN(FN L(N)) THEN R$ = "?EVEN,"
220 IF FN L(N) < 3 THEN R$ = R$ + "ONLY " + STR$(FN L(N)) + " DIGIT" + MID$("S",FN L(N) - 1, 1)
230 IF RIGHT$(R$, 1) = "," THEN R$ = LEFT$(R$, LEN(R$) - 1) : RETURN
240 IF LEFT$(R$, 1) = "?" THEN RETURN
250 IF R$ <> "" THEN R$ = "?" + R$ : RETURN
260 R$ = STR$(FN N(N))
270 IF LEN(R$) = 1 THEN R$ = "00" + R$
280 IF LEN(R$) = 2 THEN R$ = "0" + R$
290 RETURN
300 DATA123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345
310 DATA1,2,-1,-10,2002,-2002,0
</syntaxhighlight>
{{out}}
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: ?ONLY 1 DIGIT
2: ?ONLY 1 DIGIT
-1: ?ONLY 1 DIGIT
-10: ?EVEN,ONLY 2 DIGITS
2002: ?EVEN
-2002: ?EVEN
0: ?ONLY 1 DIGIT
</pre>
==={{header|BASIC256}}===
<syntaxhighlight lang="vb">function middleThreeDigits(n)
if n < 0 then n = -n
if n < 100 then return "" ## error code
if n < 1000 then return string(n)
if n < 10000 then return ""
ns = string(n)
if length(ns) mod 2 = 0 then return "" ## need to have an odd number of digits for there to be 3 middle
return mid(ns, length(ns) \ 2, 3)
end function
dim a = {123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -123451, 2, -1, -10, 2002, -2002, 0}
print "The 3 middle digits of the following numbers are : "
print
for i = 0 to 15
result = middleThreeDigits(a[i])
print a[i]; chr(9); " => ";
if result <> "" then
print result
else
print "Error: does not have 3 middle digits"
end if
next</syntaxhighlight>
{{out}}
<pre>Similar to FreeBASIC entry.</pre>
==={{header|BBC BASIC}}===
<syntaxhighlight lang="bbcbasic">REM >midthree
FOR i% = 1 TO 17
READ test%
PRINT test%; " -> "; FN_middle_three(test%)
NEXT
END
:
DATA 123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345
DATA 1, 2, -1, -10, 2002, -2002, 0
:
DEF FN_middle_three(n%)
LOCAL n$
n$ = STR$ ABS n%
CASE TRUE OF
WHEN LEN n$ < 3
= "Not enough digits"
WHEN LEN n$ MOD 2 = 0
= "Even number of digits"
OTHERWISE
= MID$(n$, LEN n$ / 2, 3)
ENDCASE</syntaxhighlight>
{{out}}
<pre> 123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> Not enough digits
2 -> Not enough digits
-1 -> Not enough digits
-10 -> Not enough digits
2002 -> Even number of digits
-2002 -> Even number of digits
0 -> Not enough digits</pre>
==={{header|FBSL}}===
<syntaxhighlight lang="qbasic">#APPTYPE CONSOLE
DIM numbers AS STRING = "123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345,1,2,-1,-10,2002,-2002,0"
DIM dict[] = Split(numbers, ",")
DIM num AS INTEGER
DIM num2 AS INTEGER
DIM powered AS INTEGER
FOR DIM i = 0 TO COUNT(dict) - 1
num2 = dict[i]
num = ABS(num2)
IF num < 100 THEN
display(num2, "is too small")
ELSE
FOR DIM j = 9 DOWNTO 1
powered = 10 ^ j
IF num >= powered THEN
IF j MOD 2 = 1 THEN
display(num2, "has even number of digits")
ELSE
display(num2, middle3(num, j))
END IF
EXIT FOR
END IF
NEXT
END IF
NEXT
PAUSE
FUNCTION display(num, msg)
PRINT LPAD(num, 11, " "), " --> ", msg
END FUNCTION
FUNCTION middle3(n, pwr)
DIM power AS INTEGER = (pwr \ 2) - 1
DIM m AS INTEGER = n
m = m \ (10 ^ power)
m = m MOD 1000
IF m = 0 THEN
RETURN "000"
ELSE
RETURN m
END IF
END FUNCTION</syntaxhighlight>
Output
<pre> 123 --> 123
12345 --> 234
1234567 --> 345
987654321 --> 654
10001 --> 000
-10001 --> 000
-123 --> 123
-100 --> 100
100 --> 100
-12345 --> 234
1 --> is too small
2 --> is too small
-1 --> is too small
-10 --> is too small
2002 --> has even number of digits
-2002 --> has even number of digits
0 --> is too small
Press any key to continue...</pre>
==={{header|IS-BASIC}}===
<syntaxhighlight lang="is-basic">100 INPUT PROMPT "Number: ":N
120 PRINT MIDDLE$(N)
130 DEF MIDDLE$(N)
140 LET N$=STR$(ABS(N))
150 IF LEN(N$)<3 THEN LET MIDDLE$="Not enough digits":EXIT DEF
160 IF MOD(LEN(N$),2)=0 THEN LET MIDDLE$="Even number of digits":EXIT DEF
170 LET P=(LEN(N$)-3)/2
180 LET MIDDLE$=N$(P+1:P+3)
190 END DEF</syntaxhighlight>
==={{header|PureBasic}}===
<syntaxhighlight lang="purebasic">Procedure.s middleThreeDigits(x.q)
Protected x$, digitCount
If x < 0: x = -x: EndIf
x$ = Str(x)
digitCount = Len(x$)
If digitCount < 3
ProcedureReturn "invalid input: too few digits"
ElseIf digitCount % 2 = 0
ProcedureReturn "invalid input: even number of digits"
EndIf
ProcedureReturn Mid(x$,digitCount / 2, 3)
EndProcedure
If OpenConsole()
Define testValues$ = "123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1 -10 2002 -2002 0"
Define i, value.q, numTests = CountString(testValues$, " ") + 1
For i = 1 To numTests
value = Val(StringField(testValues$, i, " "))
PrintN(RSet(Str(value), 12, " ") + " : " + middleThreeDigits(value))
Next
Print(#crlf$ + #crlf$ + "Press ENTER to exit"): Input()
CloseConsole()
EndIf</syntaxhighlight>
Sample output:
<pre> 123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : invalid input: too few digits
2 : invalid input: too few digits
-1 : invalid input: too few digits
-10 : invalid input: too few digits
2002 : invalid input: even number of digits
-2002 : invalid input: even number of digits
0 : invalid input: too few digits</pre>
==={{header|Run BASIC}}===
<syntaxhighlight lang="runbasic">x$ = "123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0"
while word$(x$,i+1,",") <> ""
i = i + 1
a1$ = trim$(word$(x$,i,","))
if left$(a1$,1) = "-" then a$ = mid$(a1$,2) else a$ = a1$
if (len(a$) and 1) = 0 or len(a$) < 3 then
print a1$;chr$(9);" length < 3 or is even"
else
print mid$(a$,((len(a$)-3)/2)+1,3);" ";a1$
end if
wend
end</syntaxhighlight>
<pre>123 123
234 12345
345 1234567
654 987654321
000 10001
000 -10001
123 -123
100 -100
100 100
234 -12345
1 length < 3 or is even
2 length < 3 or is even
-1 length < 3 or is even
-10 length < 3 or is even
2002 length < 3 or is even
-2002 length < 3 or is even
0 length < 3 or is even</pre>
==={{header|Yabasic}}===
<syntaxhighlight lang="vb">sub middleThreeDigits$ (n)
if n < 0 n = -n
if n < 100 return "" // error code
if n < 1000 return str$(n)
if n < 10000 return ""
ns$ = str$(n)
if mod(len(ns$), 2) = 0 return "" // need to have an odd number of digits for there to be 3 middle
return mid$(ns$, len(ns$) / 2, 3)
end sub
dim a(16)
a(0) = 123 : a(1) = 12345 : a(2) = 1234567
a(3) = 987654321 : a(4) = 10001 : a(5) = -10001
a(6) = -123 : a(7) = -100 : a(8) = 100
a(9) = -123451
a(10) = 2 : a(11) = -1 : a(12) = -10
a(13) = 2002 : a(14) = -2002 : a(15) = 0
print "The 3 middle digits of the following numbers are : \n"
for i = 1 to 16
result$ = middleThreeDigits$(a(i))
print a(i), "\t => ";
if result$ <> "" then
print result$
else
print "Error: does not have 3 middle digits"
fi
next</syntaxhighlight>
{{out}}
<pre>Similar to FreeBASIC entry.</pre>
=={{header|Batch File}}==
<syntaxhighlight lang="dos">@echo off
setlocal enabledelayedexpansion
%== Initialization ==%
set "numbers=123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0"
%== The Main Thing ==%
for %%N in (%numbers%) do (
call :middle3 %%N
)
echo.
pause
exit /b 0
%==/The Main Thing ==%
%== The Procedure ==%
:middle3
set str=%1
%== Making sure that str is positive ==%
if !str! lss 0 set /a str*=-1
%== Alternative for finding the string length ==%
%== But this has a limit of 1000 characters ==%
set leng=0&if not "!str!"=="" for /l %%. in (0,1,1000) do if not "!str:~%%.,1!"=="" set /a leng+=1
if !leng! lss 3 (
echo.%~1: [ERROR] Input too small.
goto :EOF
)
set /a "test2=leng %% 2,trimmer=(leng - 3) / 2"
if !test2! equ 0 (
echo.%~1: [ERROR] Even number of digits.
goto :EOF
)
%== Passed the tests. Now, really find the middle 3 digits... ==%
if !trimmer! equ 0 (
echo.%~1: !str!
) else (
echo.%~1: !str:~%trimmer%,-%trimmer%!
)
goto :EOF
%==/The Procedure ==%</syntaxhighlight>
{{Out}}
<pre>123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: [ERROR] Input too small.
2: [ERROR] Input too small.
-1: [ERROR] Input too small.
-10: [ERROR] Input too small.
2002: [ERROR] Even number of digits.
-2002: [ERROR] Even number of digits.
0: [ERROR] Input too small.
Press any key to continue . . .</pre>
=={{header|Befunge}}==
Reads the integer value from stdin and writes the middle three digits (or an error message) to stdout.
<syntaxhighlight lang="befunge">>&>:0`2*1-*0>v
v+*86%+55:p00<
>\55+/:00g1+\|
v3_v#*%2\`2::<
->@>0".rorrE"v
2^,+55_,#!>#:<
>/>\#<$#-:#1_v
>_@#<,+55,,,$<</syntaxhighlight>
{{out}} (multiple runs)
<pre>123
123
12345
234
1234567
345
987654321
654
10001
000
-10001
000
-123
123
-100
100
100
100
-12345
234
1
Error.
2
Error.
-1
Error.
-10
Error.
2002
Error.
-2002
Error.
0
Error.</pre>
=={{header|Bracmat}}==
<syntaxhighlight lang="bracmat">( ( middle3
= x p
. @(!arg:? [?p:? [(1/2*!p+-3/2) %?x [(1/2*!p+3/2) ?)
& !x
| !arg
( !p:<3&"is too small"
| "has even number of digits"
)
)
& 123 12345 1234567 987654321 10001 -10001 -123 -100 100
-12345 1 2 -1 -10 2002 -2002 0
: ?L
& whl'(!L:%?e ?L&out$(middle3$!e))
&
);
</syntaxhighlight>
Output:
<pre>123
234
345
654
000
000
123
100
100
234
1 is too small
2 is too small
-1 is too small
-10 is too small
2002 has even number of digits
-2002 has even number of digits
0 is too small</pre>
=={{header|Burlesque}}==
<syntaxhighlight lang="blsq">
blsq ) {123 12345 1234567 987654321 -10001 -123}{XX{~-}{L[3.>}w!m]\[}m[uN
123
234
345
654
000
123
</syntaxhighlight>
<tt>m]\[</tt> and <tt>uN</tt> are just for displaying it nicely.
=={{header|C}}==
This code is followed by its output.
<syntaxhighlight lang="c">
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// we return a static buffer; caller wants it, caller copies it
char * mid3(int n)
{
static char buf[32];
int l;
sprintf(buf, "%d", n > 0 ? n : -n);
l = strlen(buf);
if (l < 3 || !(l & 1)) return 0;
l = l / 2 - 1;
buf[l + 3] = 0;
return buf + l;
}
int main(void)
{
int x[] = {123, 12345, 1234567, 987654321, 10001, -10001,
-123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0,
1234567890};
int i;
char *m;
for (i = 0; i < sizeof(x)/sizeof(x[0]); i++) {
if (!(m = mid3(x[i])))
m = "error";
printf("%d: %s\n", x[i], m);
}
return 0;
}</syntaxhighlight>
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: error
2: error
-1: error
-10: error
2002: error
-2002: error
0: error
1234567890: error
</pre>
===Alternative Version===
This code has been extensively rewritten. The original was purely interactive and had to be invoked each time from the console. It also did not produce the correct answer.
<syntaxhighlight lang="c">
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void midThree(char arg[])
{
char output[4];
int midPoint;
arg[0]=='-'?midPoint = ((strlen(arg) + 1) / 2):midPoint = ((strlen(arg) + 1) / 2) - 1;
if(strlen(arg) < 3)
{
printf("Error, %d is too short.\n",atoi(arg));
return ;
}
else if(strlen(arg) == 4 || strlen(arg) == 3)
{
printf("Error, %d has %d digits, no 3 middle digits.\n",atoi(arg),arg[0]=='-'?strlen(arg)-1:strlen(arg));
return ;
}
else{
for(int i=0; i<3; i++)
{
}
output[3] = '\0';
printf("The middle three digits of %s are %s.\n",arg,output);
}}
int main(int argc, char * argv[])
{
char input[50];
int x[] = {123, 12345, 1234567, 987654321, 10001, -10001,
-123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0,
1234567890},i;
if(argc < 2)
{
printf("Examples with preloaded data shown below :\n");
for(i=0;i<18;i++)
{
midThree(itoa(x[i],argv[0],10));
}
return 1;
}
else
{
sprintf(input,"%d",atoi(argv[1]));
midThree(argv[1]);
return 0;
}
}</syntaxhighlight>
{{out}}
<pre>
Usage: C:\TurboC++\Disk\TurboC3\BIN\rosmid3_2.exe <integer>
Examples with preloaded data shown below :
Error, 123 has 3 digits, no 3 middle digits.
The middle three digits of 12345 are 234.
The middle three digits of 987654321 are 654.
The middle three digits of 10001 are 000.
The middle three digits of -10001 are 000.
Error, -123 has 3 digits, no 3 middle digits.
Error, -100 has 3 digits, no 3 middle digits.
Error, 100 has 3 digits, no 3 middle digits.
The middle three digits of -12345 are 234.
Error, 1 is too short.
Error, 2 is too short.
Error, -1 is too short.
Error, -10 has 2 digits, no 3 middle digits.
Error, 2002 has 4 digits, no 3 middle digits.
Error, -2002 has 4 digits, no 3 middle digits.
Error, 0 is too short.
The middle three digits of 1234567890 are 456.
</pre>
=={{header|C++}}==
<syntaxhighlight lang="cpp">#include <iostream>
std::string middleThreeDigits(int n)
{
auto number = std::to_string(std::abs(n));
auto length = number.size();
if (length < 3) {
return "less than three digits";
} else if (length % 2 == 0) {
return "even number of digits";
} else {
return number.substr(length / 2 - 1, 3);
}
}
int main()
{
1, 2, -1, -10, 2002, -2002,
for (auto&& v : values) {
std::cout << "
}
}
</syntaxhighlight>
{{out}}
<pre>middleThreeDigits(123): 123
middleThreeDigits(12345): 234
middleThreeDigits(1234567): 345
middleThreeDigits(987654321): 654
middleThreeDigits(10001): 000
middleThreeDigits(-10001): 000
middleThreeDigits(-123): 123
middleThreeDigits(-100): 100
middleThreeDigits(100): 100
middleThreeDigits(-12345): 234
middleThreeDigits(1): less than three digits
middleThreeDigits(2): less than three digits
middleThreeDigits(-1): less than three digits
middleThreeDigits(-10): less than three digits
middleThreeDigits(2002): even number of digits
middleThreeDigits(-2002): even number of digits
middleThreeDigits(0): less than three digits</pre>
=={{header|C_sharp|C#}}==
<syntaxhighlight lang="csharp">using System;
namespace RosettaCode
{
class Program
{
static void Main(string[] args)
{
string text = Math.Abs(int.Parse(Console.ReadLine())).ToString();
Console.WriteLine(text.Length < 2 || text.Length % 2 == 0 ? "Error" : text.Substring((text.Length - 3) / 2, 3));
}
}
}</syntaxhighlight>
{{out}}
<pre>123:123
12345:234
1234567:345
987654321:654
10001:000
-10001:000
-123:123
-100:100
100:100
-12345:234
1:Error
2:Error
-1:Error
-10:Error
2002:Error
-2002:Error
0:Error
</pre>
=={{header|Clojure}}==
<syntaxhighlight lang="clojure">(defn middle3
[v]
(let [digit-str (str (Math/abs v))
len (count digit-str)]
(cond
(< len 3) :too-short
(even? len) :even-digit-count
:else (let [half (/ len 2)]
(subs digit-str (- half 1) (+ half 2))))))
(clojure.pprint/print-table
(for [i [123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345
1 2 -1 -10 2002 -2002 0]]
{:i i :middle-3 (middle3 i)}))
</syntaxhighlight>
{{out}}
<pre>
| :i | :middle-3 |
|-----------+-------------------|
| 123 | 123 |
| 12345 | 234 |
| 1234567 | 345 |
| 987654321 | 654 |
| 10001 | 000 |
| -10001 | 000 |
| -123 | 123 |
| -100 | 100 |
| 100 | 100 |
| -12345 | 234 |
| 1 | :too-short |
| 2 | :too-short |
| -1 | :too-short |
| -10 | :too-short |
| 2002 | :even-digit-count |
| -2002 | :even-digit-count |
| 0 | :too-short |
</pre>
=={{header|CLU}}==
<syntaxhighlight lang="clu">middle_three_digits = proc (n: int) returns (string)
signals (too_small, even_length)
s: string := int$unparse(int$abs(n))
if string$size(s) < 3 then signal too_small end
if string$size(s) // 2 = 0 then signal even_length end
return(string$substr(s, string$size(s)/2, 3))
end middle_three_digits
start_up = proc ()
po: stream := stream$primary_output()
tests: sequence[int] := sequence[int]$
[123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345,
1,2,-1,-10,2002,-2002,0]
for test: int in sequence[int]$elements(tests) do
stream$putright(po, int$unparse(test) || ": ", 11)
stream$putl(po, middle_three_digits(test))
except
when too_small: stream$putl(po, "Too small")
when even_length: stream$putl(po, "Even length")
end
end
end start_up</syntaxhighlight>
{{out}}
<pre> 123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: Too small
2: Too small
-1: Too small
-10: Too small
2002: Even length
-2002: Even length
0: Too small</pre>
=={{header|COBOL}}==
<syntaxhighlight lang="cobol">identification division.
program-id. middle3.
environment division.
data division.
working-storage section.
01 num pic 9(9).
88 num-too-small values are -99 thru 99.
01 num-disp pic ---------9.
01 div pic 9(9).
01 mod pic 9(9).
01 mod-disp pic 9(3).
01 digit-counter pic 999.
01 digit-div pic 9(9).
88 no-more-digits value 0.
01 digit-mod pic 9(9).
88 is-even value 0.
01 multiplier pic 9(9).
01 value-items.
05 filler pic s9(9) value 123.
05 filler pic s9(9) value 12345.
05 filler pic s9(9) value 1234567.
05 filler pic s9(9) value 987654321.
05 filler pic s9(9) value 10001.
05 filler pic s9(9) value -10001.
05 filler pic s9(9) value -123.
05 filler pic s9(9) value -100.
05 filler pic s9(9) value 100.
05 filler pic s9(9) value -12345.
05 filler pic s9(9) value 1.
05 filler pic s9(9) value 2.
05 filler pic s9(9) value -1.
05 filler pic s9(9) value -10.
05 filler pic s9(9) value 2002.
05 filler pic s9(9) value -2002.
05 filler pic s9(9) value 0.
01 value-array redefines value-items.
05 items pic s9(9) occurs 17 times indexed by item.
01 result pic x(20).
procedure division.
10-main.
perform with test after varying item from 1 by 1 until items(item) = 0
move items(item) to num
move items(item) to num-disp
perform 20-check
display num-disp " --> " result
end-perform.
stop run.
20-check.
if num-too-small
move "Number too small" to result
exit paragraph
end-if.
perform 30-count-digits.
divide digit-counter by 2 giving digit-div remainder digit-mod.
if is-even
move "Even number of digits" to result
exit paragraph
end-if.
*> if digit-counter is 5, mul by 10
*> if digit-counter is 7, mul by 100
*> if digit-counter is 9, mul by 1000
if digit-counter > 3
compute multiplier rounded = 10 ** (((digit-counter - 5) / 2) + 1)
divide num by multiplier giving num
divide num by 1000 giving div remainder mod
move mod to mod-disp
else
move num to mod-disp
end-if.
move mod-disp to result.
exit paragraph.
30-count-digits.
move zeroes to digit-counter.
move num to digit-div.
perform with test before until no-more-digits
divide digit-div by 10 giving digit-div remainder digit-mod
add 1 to digit-counter
end-perform.
exit paragraph.</syntaxhighlight>
Output
<pre> 123 --> 123
12345 --> 234
1234567 --> 345
987654321 --> 654
10001 --> 000
-10001 --> 000
-123 --> 123
-100 --> 100
100 --> 100
-12345 --> 234
1 --> Number too small
2 --> Number too small
-1 --> Number too small
-10 --> Number too small
2002 --> Even number of digit
-2002 --> Even number of digit
0 --> Number too small</pre>
Optimised version
<syntaxhighlight lang="cobol">identification division.
program-id. middle3.
environment division.
data division.
working-storage section.
01 value-items.
05 filler pic s9(9) value 123.
05 filler pic s9(9) value 12345.
05 filler pic s9(9) value 1234567.
05 filler pic s9(9) value 987654321.
05 filler pic s9(9) value 10001.
05 filler pic s9(9) value -10001.
05 filler pic s9(9) value -123.
05 filler pic s9(9) value -100.
05 filler pic s9(9) value 100.
05 filler pic s9(9) value -12345.
05 filler pic s9(9) value 1.
05 filler pic s9(9) value 2.
05 filler pic s9(9) value -1.
05 filler pic s9(9) value -10.
05 filler pic s9(9) value 2002.
05 filler pic s9(9) value -2002.
05 filler pic s9(9) value 0.
01 value-array redefines value-items.
05 items pic s9(9) occurs 17 times indexed by item.
01 num pic 9(9).
01 num-disp pic ---------9.
01 num2 pic 9(9).
01 power pic 9.
01 power10 pic 9(16).
01 three-digits pic 999.
01 result pic X(20).
01 flag pic 9.
88 done value 1.
procedure division.
01-setup.
perform 02-outer with test after varying item from 1 by 1 until items(item) = 0.
stop run.
02-outer.
move items(item) to num.
move items(item) to num-disp.
if num less than 100
move "too small" to result
else
perform 03-inner with test after varying power from 9 by -1 until power = 1 or done
end-if.
display num-disp " --> " result.
exit paragraph.
03-inner.
move 0 to flag.
compute power10 = 10 ** power.
if num >= power10
move 1 to flag
if function mod(power,2) = 1
move "even number digits" to result
else
move num to num2
compute num2 = num2 / ( 10 ** (( power / 2 ) - 1 ))
move function mod(num2,1000) to three-digits
move three-digits to result
end-if
end-if.
</syntaxhighlight>
Output
<pre> 123 --> 123
12345 --> 234
1234567 --> 345
987654321 --> 654
10001 --> 000
-10001 --> 000
-123 --> 123
-100 --> 100
100 --> 100
-12345 --> 234
1 --> too small
2 --> too small
-1 --> too small
-10 --> too small
2002 --> even number digits
-2002 --> even number digits
0 --> too small
</pre>
=={{header|Common Lisp}}==
===Solution #1===
<syntaxhighlight lang="lisp">
(defun mid3 (n)
(let ((a (abs n))
(hmd)) ; how many digits
(labels ((give (fmt &optional x y) (return-from mid3 (format nil fmt x y)))
(need (x) (give "Need ~a digits, not ~d." x hmd))
(nbr (n) (give "~3,'0d" n)))
(when (zerop n) (give "Zero is 1 digit"))
(setq hmd (truncate (1+ (log a 10))))
(cond ((< hmd 3) (need "3+"))
((= hmd 3) (nbr a))
((evenp hmd) (need "odd number of"))
(t (nbr (mod (truncate a (expt 10 (/ (- hmd 3) 2))) 1000)))))))
</syntaxhighlight>
Test code:
<syntaxhighlight lang="lisp">
(loop as n in '(123 12345 1234567 987654321
10001 -10001 -123 -100 100 -12345
1 2 -1 -10 2002 -2002 0)
do (format t "~d:~12t~a~%" n (mid3 n)))
</syntaxhighlight>
{{out}}
<pre>123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: Need 3+ digits, not 1.
2: Need 3+ digits, not 1.
-1: Need 3+ digits, not 1.
-10: Need 3+ digits, not 2.
2002: Need odd number of digits, not 4.
-2002: Need odd number of digits, not 4.
0: Zero is 1 digit</pre>
===Solution #2===
<syntaxhighlight lang="lisp">
(defun mid3 (i)
(let ((ch-vec (coerce (format nil "~A" (abs i)) 'vector)))
(when (evenp (length ch-vec))
(return-from mid3
(format nil "Error: The number representation must have an odd ~
number of digits.")))
(when (and (< i 100)
(> i -100))
(return-from mid3
(format nil "Error: Must be >= 100 or <= -100.")))
(let ((half (/ (1- (length ch-vec)) 2)))
(return-from mid3 (format nil "~A~A~A"
(elt ch-vec (1- half))
(elt ch-vec half)
(elt ch-vec (1+ half))))
)))
</syntaxhighlight>
Test code:
<syntaxhighlight lang="lisp">
(defun test-mid3 ()
(let ((test-lst (list 123
12345
1234567
987654321
10001
-10001
-123
-100
100
-12345
1
2
-1
-10
2002
-2002
0
)))
(labels
((run-tests (lst)
(cond ((null lst)
nil)
(t
(format t "~A ~15T ~A~%" (first lst) (mid3 (first lst)))
(run-tests (rest lst))))))
(run-tests test-lst)))
(values)
)
</syntaxhighlight>
{{out}}
<pre>
123 123
12345 234
1234567 345
987654321 654
10001 000
-10001 000
-123 123
-100 100
100 100
-12345 234
1 Error: Must be >= 100 or <= -100.
2 Error: Must be >= 100 or <= -100.
-1 Error: Must be >= 100 or <= -100.
-10 Error: The number representation must have an odd number of digits.
2002 Error: The number representation must have an odd number of digits.
-2002 Error: The number representation must have an odd number of digits.
0 Error: Must be >= 100 or <= -100.
</pre>
=={{header|D}}==
<
string middleThreeDigits(T)(in T n) pure nothrow if (isIntegral!T) {
auto s = n < 0 ? n.text
auto len = s.length;
if (len < 3 || len % 2 == 0)
Line 128 ⟶ 2,311:
immutable passing = [123, 12345, 1234567, 987654321, 10001, -10001,
-123, -100, 100, -12345, long.min, long.max];
foreach (immutable n; passing)
writefln("middleThreeDigits(%s): %s", n, middleThreeDigits(n));
immutable failing = [1, 2, -1, -10, 2002, -2002, 0,int.min,int.max];
foreach (immutable n; failing)
writefln("middleThreeDigits(%s): %s", n, middleThreeDigits(n));
}</
{{out}}
<pre>middleThreeDigits(123): 123
Line 160 ⟶ 2,343:
===Alternative Version===
This longer version gives a stronger typed output, and it tries to be faster avoiding conversions to string.
<
/// Returns a string with the error, or the three digits.
Line 246 ⟶ 2,429:
writefln("middleThreeDigits(cast(short)%d): %s", n, mtd);
}
}</
{{out}}
<pre>middleThreeDigits(123): 123
Line 295 ⟶ 2,478:
middleThreeDigits(cast(short)-32768): 276</pre>
=={{header|Dart}}==
<syntaxhighlight lang="text">
import'dart:math';
int length(int x)
{
int i,y;
for(i=0;;i++)
{
y=pow(10,i);
if(x%y==x)
break;
}
return i;
}
int middle(int x,int l)
{
int a=(x/10)-((x%10)/10);
int b=a%(pow(10,l-2));
int l2=length(b);
if(l2==3)
{
return b;
}
if(l2!=3)
{
return middle(b,l2);
}
return 0;
}
main()
{
int x=-100,y;
if(x<0)
x=-x;
int l=length(x);
if(l.isEven||x<100)
{print('error');}
if(l==3)
{print('$x');}
if(l.isOdd&& x>100)
{
y=middle(x,l);
print('$y');
}
}
</syntaxhighlight>
=={{header|DCL}}==
<syntaxhighlight lang="text">$ list = "123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345,1,2,-1,-10,2002,-2002,0"
$ i = 0
$ loop:
$ number = f$element( i, ",", list )
$ if number .eqs. "," then $ exit
$ abs_number = number - "-"
$ len = f$length( abs_number )
$ if len .lt. 3 .or. .not. len
$ then
$ write sys$output f$fao( "!9SL: ", f$integer( number )), "has no middle three"
$ else
$ write sys$output f$fao( "!9SL: ", f$integer( number )), f$extract( ( len - 3 ) / 2, 3, abs_number )
$ endif
$ i = i + 1
$ goto loop</syntaxhighlight>
{{out}}
<pre>$ @middle_three_digits
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: has no middle three
2: has no middle three
-1: has no middle three
-10: has no middle three
2002: has no middle three
-2002: has no middle three
0: has no middle three</pre>
=={{header|Delphi}}==
See [https://rosettacode.org/wiki/Middle_three_digits#Pascal Pascal].
=={{header|EasyLang}}==
<syntaxhighlight lang="easylang">
func$ midThreeDigits num .
trueNumber$ = abs num
if (len trueNumber$ < 3) or (len trueNumber$ mod 2 = 0)
r$ = "error"
else
r$ = substr trueNumber$ ((len trueNumber$ - 3) / 2 + 1) 3
.
return r$
.
numbers[] = [ 123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1 -10 2002 -2002 0 ]
for i in numbers[]
print midThreeDigits i
.
</syntaxhighlight>
{{out}}
<pre>
123
234
345
654
000
000
123
100
100
234
error
error
error
error
error
error
error
</pre>
=={{header|Eiffel}}==
<syntaxhighlight lang="eiffel">
class
APPLICATION
create
make
feature
make
-- Test of middle_three_digits.
local
test_1, test_2: ARRAY [INTEGER]
do
test_1 := <<123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345>>
test_2 := <<1, 2, -1, -10, 2002, -2002, 0>>
across
test_1 as t
loop
io.put_string ("The middle three digits of " + t.item.out + " are: %T ")
io.put_string (middle_three_digits (t.item) + "%N")
end
across
test_2 as t
loop
io.put_string ("The middle three digits of " + t.item.out + " are: %T")
io.put_string (middle_three_digits (t.item) + "%N")
end
end
middle_three_digits (n: INTEGER): STRING
-- The middle three digits of 'n'.
local
k, i: INTEGER
in: STRING
do
create in.make_empty
in := n.out
if n < 0 then
in.prune ('-')
end
create Result.make_empty
if in.count < 3 then
io.put_string (" Not enough digits. ")
elseif in.count \\ 2 = 0 then
io.put_string (" Even number of digits. ")
else
i := (in.count - 3) // 2
from
k := i + 1
until
k > i + 3
loop
Result.extend (in.at (k))
k := k + 1
end
end
ensure
length_is_three: Result.count = 3 or Result.count = 0
end
end
</syntaxhighlight>
{{out}}
<pre>
The middle three digits of 123 are: 123
The middle three digits of 12345 are: 234
The middle three digits of 1234567 are: 345
The middle three digits of 987654321 are: 654
The middle three digits of 10001 are: 000
The middle three digits of -10001 are: 000
The middle three digits of -123 are: 123
The middle three digits of -100 are: 100
The middle three digits of 100 are: 100
The middle three digits of -12345 are: 234
The middle three digits of 1 are: Not enough digits.
The middle three digits of 2 are: Not enough digits.
The middle three digits of -1 are: Not enough digits.
The middle three digits of -10 are: Not enough digits.
The middle three digits of 2002 are: Even number of digits.
The middle three digits of -2002 are: Even number of digits.
The middle three digits of 0 are: Not enough digits.
</pre>
=={{header|Elena}}==
ELENA 6.x :
<syntaxhighlight lang="elena">import system'routines;
import extensions;
middleThreeDigits(int n)
{
string s := n.Absolute.toString();
int len := s.Length;
if(len<3)
{
InvalidArgumentException.new("n must have 3 digits or more").raise()
}
else if(len.isEven())
{
InvalidArgumentException.new("n must have an odd number of digits").raise()
};
int mid := len / 2;
^ s.Substring(mid-1,3)
}
public program()
{
new int[]{123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0}
.forEach::(n)
{
console.printLine("middleThreeDigits(",n,"):",middleThreeDigits(n) \\ on::(e => e.Message))
}
}</syntaxhighlight>
{{out}}
<pre>
middleThreeDigits(123):123
middleThreeDigits(12345):234
middleThreeDigits(1234567):345
middleThreeDigits(987654321):654
middleThreeDigits(10001):000
middleThreeDigits(-10001):000
middleThreeDigits(-123):123
middleThreeDigits(-100):100
middleThreeDigits(100):100
middleThreeDigits(-12345):234
middleThreeDigits(1):n must have 3 digits or more
middleThreeDigits(2):n must have 3 digits or more
middleThreeDigits(-1):n must have 3 digits or more
middleThreeDigits(-10):n must have 3 digits or more
middleThreeDigits(2002):n must have an odd number of digits
middleThreeDigits(-2002):n must have an odd number of digits
middleThreeDigits(0):n must have 3 digits or more
</pre>
=={{header|Elixir}}==
<syntaxhighlight lang="elixir">defmodule Middle do
def three(num) do
n = num |> abs |> to_string
case {n,String.length(n) > 2,even?(n)} do
{n, true, false} ->
cut(n)
{_, false, _} ->
raise "Number must have at least three digits"
{_, _, true} ->
raise "Number must have an odd number of digits"
end
end
defp even?(n), do: rem(String.length(n),2) == 0
defp cut(n), do: String.slice(n,(div(String.length(n),2) - 1),3)
end
valids = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345]
Enum.each(valids, fn n -> :io.format "~10w : ~s~n", [n, Middle.three(n)] end)
errors = [1, 2, -1, -10, 2002, -2002, 0]
Enum.each(errors, fn n ->
:io.format "~10w : ", [n]
try do
IO.puts Middle.three(n)
rescue
e -> IO.puts e.message
end
end)</syntaxhighlight>
{{out}}
<pre>
123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : Number must have at least three digits
2 : Number must have at least three digits
-1 : Number must have at least three digits
-10 : Number must have at least three digits
2002 : Number must have an odd number of digits
-2002 : Number must have an odd number of digits
0 : Number must have at least three digits
</pre>
=={{header|Erlang}}==
<syntaxhighlight lang="erlang">%
-module(middle_three_digits).
-export([main/0]).
main() ->
digits(123),
digits(12345),
digits(1234567),
digits(987654321),
digits(10001),
digits(-10001),
digits(-123),
digits(-100),
digits(100),
digits(-12345),
digits(1),
digits(2),
digits(-1),
digits(-10),
digits(2002),
digits(-2002),
digits(0).
digits(N) when N < 0 ->
digits(-N);
digits(N) when (N div 100) =:= 0 ->
io:format("too small\n");
digits(N) ->
K=length(integer_to_list(N)),
if (K rem 2) =:= 0 ->
io:format("even number of digits\n");
true ->
loop((K-3) div 2 , N)
end.
loop(0, N) ->
io:format("~3..0B~n",[N rem 1000]);
loop(X,N) when X>0 ->
loop(X-1, N div 10).
</syntaxhighlight>
{{out}}
<pre>123
234
345
654
000
000
123
100
100
234
too small
too small
too small
too small
even number of digits
even number of digits
too small
ok
</pre>
=={{header|ERRE}}==
<syntaxhighlight lang="erre">
PROGRAM MIDDLE
!$DOUBLE
FUNCTION LUNG(N)
LUNG=LEN(STR$(INT(ABS(N))))+1
END FUNCTION
FUNCTION NCNT(N)
NCNT=VAL(MID$(STR$(INT(ABS(N))),(LUNG(N)-1)/2,3))
END FUNCTION
FUNCTION EVEN(N)
EVEN=INT(N/2)=N/2
END FUNCTION
PROCEDURE NUMBER_EXAM(N->R$)
R$="" LG%=LUNG(N)-2
IF EVEN(LG%) THEN R$="?EVEN," END IF
IF LG%<3 THEN
R$=R$+"ONLY"+STR$(LG%)+" DIGIT"
IF LG%=1 THEN
R$=R$+"S"
END IF
END IF
IF RIGHT$(R$,1)="," THEN R$=LEFT$(R$,LEN(R$)-1) EXIT PROCEDURE END IF
IF LEFT$(R$,1)="?" THEN EXIT PROCEDURE END IF
IF R$<>"" THEN R$="?"+R$ EXIT PROCEDURE END IF
R$=STR$(NCNT(N))
IF LEFT$(R$,1)=" " THEN R$=MID$(R$,2) END IF
IF LEN(R$)=1 THEN R$="00"+R$ END IF
IF LEN(R$)=2 THEN R$="0"+R$ END IF
END PROCEDURE
BEGIN
DATA(123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345)
DATA(1,2,-1,-10,2002,-2002,0)
FOR I%=1 TO 17 DO
READ(N)
PRINT(N;" ",)
NUMBER_EXAM(N->R$)
PRINT(R$)
END FOR
END PROGRAM
</syntaxhighlight>
{{out}}
<pre>
123 123
12345 234
1234567 345
987654321 654
10001 000
-10001 000
-123 123
-100 100
100 100
-12345 234
1 ?ONLY 1 DIGITS
2 ?ONLY 1 DIGITS
-1 ?ONLY 1 DIGITS
-10 ?EVEN,ONLY 2 DIGIT
2002 ?EVEN
-2002 ?EVEN
0 ?ONLY 1 DIGITS
</pre>
=={{header|Factor}}==
<syntaxhighlight lang="text">USING: combinators formatting io kernel math math.parser
sequences ;
IN: rosetta-code.middle-three-digits
CONSTANT: test-values {
123 12345 1234567 987654321 10001 -10001
-123 -100 100 -12345 1 2 -1 -10 2002 -2002 0
}
: (middle-three) ( str -- str' )
[ midpoint@ [ 1 - ] [ 2 + ] bi ] [ subseq ] bi ;
: too-short ( -- )
"Number must have at least three digits." print ;
: number-even ( -- )
"Number must have an odd number of digits." print ;
: middle-three ( n -- )
abs number>string {
{ [ dup length 3 < ] [ drop too-short ] }
{ [ dup length even? ] [ drop number-even ] }
[ (middle-three) print ]
} cond ;
: main ( -- )
test-values [ dup "%9d : " printf middle-three ] each ;
MAIN: main</syntaxhighlight>
{{out}}
<pre>
123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : Number must have at least three digits.
2 : Number must have at least three digits.
-1 : Number must have at least three digits.
-10 : Number must have at least three digits.
2002 : Number must have an odd number of digits.
-2002 : Number must have an odd number of digits.
0 : Number must have at least three digits.
</pre>
=={{header|Forth}}==
This is a problem, which is easily solved in Forth. It converts the number to a string and checks it length. If the number does not represent a printable string, it returns an empty string.
<syntaxhighlight lang="forth">: middle3 ( n1 -- a n2)
abs s>d <# #s #> dup 2/ 0<> over 1 and 0<> and
if 2/ 1- chars + 3 else drop 0 then
;</syntaxhighlight>
=={{header|Fortran}}==
Please find compilation instructions along with the output for the examples in the comments at the beginning of the file. This program was produced in an Ubuntu distribution of the GNU/linux system.
<syntaxhighlight lang="fortran">
!-*- mode: compilation; default-directory: "/tmp/" -*-
!Compilation started at Sat Jun 1 14:48:41
!
!a=./f && make $a && OMP_NUM_THREADS=2 $a < unixdict.txt # some of the compilation options and redirection from unixdict.txt are vestigial.
!gfortran -std=f2008 -Wall -fopenmp -ffree-form -fall-intrinsics -fimplicit-none f.f08 -o f
! 123 123
! 12345 234
! 1234567 345
! 987654321 654
! 10001 000
! -10001 000
! -123 123
! -100 100
! 100 100
! -12345 234
! 1 Too short
! 2 Too short
! -1 Too short
! -10 Too short
! 2002 Digit count too even
! -2002 Digit count too even
! 0 Too short
!
!Compilation finished at Sat Jun 1 14:48:41
program MiddleMuddle
integer, dimension(17) :: itest, idigits
integer :: i, n
data itest/123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345,1,2,-1,-10,2002,-2002,0/
do i = 1, size(itest)
call antibase(10, abs(itest(i)), idigits, n)
write(6,'(i20,2x,a20)') itest(i), classifym3(idigits, n)
if (0 .eq. itest(i)) exit
end do
contains
logical function even(n)
integer, intent(in) :: n
even = 0 .eq. iand(n,1)
end function even
function classifym3(iarray, n) result(s)
integer, dimension(:), intent(in) :: iarray
integer, intent(in) :: n
character(len=20) :: s
integer :: i,m
if (n < 3) then
s = 'Too short'
else if (even(n)) then
s = 'Digit count too even'
else
m = (n+1)/2
write(s,'(3i1)')(iarray(i), i=m+1,m-1,-1)
end if
end function classifym3
subroutine antibase(base, m, digits, n) ! digits ordered by increasing significance
integer, intent(in) :: base, m
integer, intent(out) :: n ! the number of digits
integer, dimension(:), intent(out) :: digits
integer :: em
em = m
do n=1, size(digits)
digits(n) = mod(em, base)
em = em / base
if (0 .eq. em) return
end do
stop 'antibase ran out of space to store result'
end subroutine antibase
end program MiddleMuddle
</syntaxhighlight>
=={{header|FreeBASIC}}==
<syntaxhighlight lang="freebasic">' FB 1.05.0 Win64
Function middleThreeDigits (n As Integer) As String
If n < 0 Then n = -n
If n < 100 Then Return "" '' error code
If n < 1000 Then Return Str(n)
If n < 10000 Then Return ""
Dim ns As String = Str(n)
If Len(ns) Mod 2 = 0 Then Return "" '' need to have an odd number of digits for there to be 3 middle
Return Mid(ns, Len(ns) \ 2, 3)
End Function
Dim a(1 To 16) As Integer => _
{123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -123451, 2, -1, -10, 2002, -2002, 0}
Dim As Integer i
Dim As String result
Print "The 3 middle digits of the following numbers are : "
Print
For i = 1 To 16
result = middleThreeDigits(a(i))
Print a(i), " => ";
If result <> "" Then
Print result
Else
Print "Error: does not have 3 middle digits"
End If
Next
Print
Print "Press any key to quit"
Sleep</syntaxhighlight>
{{out}}
<pre>
The 3 middle digits of the following numbers are :
123 => 123
12345 => 234
1234567 => 345
987654321 => 654
10001 => 000
-10001 => 000
-123 => 123
-100 => 100
100 => 100
-123451 => Error: does not have 3 middle digits
2 => Error: does not have 3 middle digits
-1 => Error: does not have 3 middle digits
-10 => Error: does not have 3 middle digits
2002 => Error: does not have 3 middle digits
-2002 => Error: does not have 3 middle digits
0 => Error: does not have 3 middle digits
</pre>
=={{header|FutureBasic}}==
<syntaxhighlight lang="futurebasic">
local fn MiddleThreeDigits( n as NSInteger ) as CFStringRef
CFStringRef testStr, resultStr
NSInteger length, middle
testStr = fn StringWithFormat( @"%ld", n )
testStr = fn StringByReplacingOccurrencesOfString( testStr, @"-", @"" )
length = len(testStr)
if length < 3 then resultStr = fn StringWithFormat( @"%10ld -> Error: Less than three digits.", n ) : exit fn
if length == 3 then resultStr = fn StringWithFormat( @"%10ld -> %@", n, testStr ) : exit fn
length = len(testStr)
if ( length mod 2 == 0 )
resultStr = fn StringWithFormat( @"%10ld -> Error: Even length; needs odd.", n )
else
middle = length / 2
resultStr = fn StringWithFormat( @"%10ld -> %@", n, mid( testStr, middle -1, 3 ) )
end if
end fn = resultStr
window 1, @"Middle Three Digits", ( 0, 0, 400, 300 )
NSUInteger i, count
CFArrayRef testArr
CFNumberRef tempNum
testArr = @[@123,@12345,@1234567,@987654321,@10001,@-10001,¬
@-123,@-100,@100,@-12345,@1,@2,@-1,@-10,@2002,@-2002,@0]
count = fn ArrayCount( testArr )
for i = 0 to count - 1
print fn MiddleThreeDigits( fn NumberIntegerValue( testArr[i] ) )
next
HandleEvents
</syntaxhighlight>
{{output}}
<pre style="font-size: 13px">
123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> Error: Less than three digits.
2 -> Error: Less than three digits.
-1 -> Error: Less than three digits.
-10 -> Error: Less than three digits.
2002 -> Error: Even length; needs odd.
-2002 -> Error: Even length; needs odd.
0 -> Error: Less than three digits.
</pre>
=={{header|Gambas}}==
'''[https://gambas-playground.proko.eu/?gist=ed25e84978446d65895ccd909fc092fa Click this link to run this code]'''
<syntaxhighlight lang="gambas">Public Sub Main()
Dim iList As Integer[] = [123, 12345, 1234567, 987654321, 10001,
-10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0] 'Array of integers to process
Dim sTemp As String 'Temp string
Dim siCount As Short 'Counter
Dim sAnswer As New String[] 'Array, resons for failure or 'middle three digits'
For siCount = 0 To iList.Max 'Loop through the integers
sTemp = Str(Abs(iList[siCount])) 'Convert integer to positive and place in sTemp as a string
If Len(sTemp) < 3 Then 'If sTemp has less than 3 characters then..
sAnswer.Add("This integer has less than 3 characters") 'Place text in sAnswers
Else If Even(Len(sTemp)) Then 'Else If sTemp is of even length then
sAnswer.Add("This integer has an even length") 'Place text in sAnswers
Else 'Else..
sAnswer.Add(Mid(sTemp, Int(Len(sTemp) / 2), 3)) 'Place the middle 3 digits in sAnswer
Endif
Next
For siCount = 0 To iList.Max 'Loop through the integers
Print Space$(10 - Len(Str(iList[siCount]))) &
iList[siCount] & " : " & sAnswer[siCount] 'Print out results
Next
End</syntaxhighlight>
Output:
<pre>
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : This integer has less than 3 characters
2 : This integer has less than 3 characters
-1 : This integer has less than 3 characters
-10 : This integer has less than 3 characters
2002 : This integer has an even length
-2002 : This integer has an even length
0 : This integer has less than 3 characters
</pre>
=={{header|Go}}==
Unlike most Go examples on RC, this is written as a package to show operation of the go test tool.
File m3.go:
<syntaxhighlight lang="go">package m3
import (
"errors"
"strconv"
)
var (
ErrorLT3 = errors.New("N of at least three digits required.")
ErrorEven = errors.New("N with odd number of digits required.")
)
func Digits(i int) (string, error) {
if i < 0 {
i = -i
}
if i < 100 {
return "", ErrorLT3
}
s := strconv.Itoa(i)
if len(s)%2 == 0 {
return "", ErrorEven
}
m := len(s) / 2
return s[m-1 : m+2], nil
}</syntaxhighlight>
File m3_test.go:
<syntaxhighlight lang="go">package m3_test
import (
"testing"
"m3"
)
func TestPassing(t *testing.T) {
type s struct {
i int
m string
}
tcs := []s{
{123, "123"},
{12345, "234"},
{1234567, "345"},
{987654321, "654"},
{10001, "000"},
{-10001, "000"},
}
for _, tc := range tcs {
m, err := m3.Digits(tc.i)
if err != nil {
t.Fatalf("d(%d) returned %q.", tc.i, err)
}
if m != tc.m {
t.Fatalf("d(%d) expected %q, got %q.", tc.i, tc.m, m)
}
t.Logf("d(%d) = %q.", tc.i, m)
}
}
func TestFailing(t *testing.T) {
type s struct {
i int
err error
}
tcs := []s{
{1, m3.ErrorLT3},
{2, m3.ErrorLT3},
{-1, m3.ErrorLT3},
{-10, m3.ErrorLT3},
{2002, m3.ErrorEven},
{-2002, m3.ErrorEven},
{0, m3.ErrorLT3},
}
for _, tc := range tcs {
m, err := m3.Digits(tc.i)
if err == nil {
t.Fatal("d(%d) expected error %q, got non-error %q.",
tc.i, tc.err, m)
}
if err != tc.err {
t.Fatal("d(d) expected error %q, got %q", tc.i, tc.err, err)
}
t.Logf("d(%d) returns %q", tc.i, err)
}
}</syntaxhighlight>
{{out}}
Output of go test is normally terse:
<pre>
> go test
PASS
ok m3 0.008s
</pre>
With -v (for verbose):
<pre>
> go test -v
=== RUN TestPassing-4
--- PASS: TestPassing-4 (0.00 seconds)
m3_test.go:30: d(123) = "123".
m3_test.go:30: d(12345) = "234".
m3_test.go:30: d(1234567) = "345".
m3_test.go:30: d(987654321) = "654".
m3_test.go:30: d(10001) = "000".
m3_test.go:30: d(-10001) = "000".
=== RUN TestFailing-4
--- PASS: TestFailing-4 (0.00 seconds)
m3_test.go:57: d(1) returns "N of at least three digits required."
m3_test.go:57: d(2) returns "N of at least three digits required."
m3_test.go:57: d(-1) returns "N of at least three digits required."
m3_test.go:57: d(-10) returns "N of at least three digits required."
m3_test.go:57: d(2002) returns "N with odd number of digits required."
m3_test.go:57: d(-2002) returns "N with odd number of digits required."
m3_test.go:57: d(0) returns "N of at least three digits required."
PASS
ok m3 0.008s
</pre>
=={{header|Gosu}}==
<syntaxhighlight lang="gosu">var valid = {123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345}
valid.each(\ num ->print(middleThree(num)))
var errant = {1, 2, -1, -10, 2002, -2002, 0}
errant.each(\ num ->print(middleThree(num)))
function middleThree(x: int) : String {
var s = Math.abs(x) as String
if(s.length < 3) return "Error: ${x} has less than 3 digits"
if(s.length % 2 == 0) return "Error: ${x} has an even number of digits"
var start = (s.length / 2) - 1
return s.substring(start, start + 3)
}</syntaxhighlight>
{{Output}}
<pre>123
234
345
654
000
000
123
100
100
234
Error: 1 has less than 3 digits
Error: 2 has less than 3 digits
Error: -1 has less than 3 digits
Error: -10 has less than 3 digits
Error: 2002 has an even number of digits
Error: -2002 has an even number of digits
Error: 0 has less than 3 digits
</pre>
=={{header|Groovy}}==
<syntaxhighlight lang="groovy">def middleThree(Number number) {
def text = Math.abs(number) as String
assert text.size() >= 3 : "'$number' must be more than 3 numeric digits"
assert text.size() % 2 == 1 : "'$number' must have an odd number of digits"
int start = text.size() / 2 - 1
text[start..(start+2)]
}</syntaxhighlight>
Test Code:
<syntaxhighlight lang="groovy">[123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0].each { number ->
def text = (number as String).padLeft(10)
try {
println "$text: ${middleThree(number)}"
} catch(AssertionError error) {
println "$text cannot be converted: $error.message"
}
}</syntaxhighlight>
Output:
<pre> 123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1 cannot be converted: '1' must be more than 3 numeric digits. Expression: (text.size() >= 3)
2 cannot be converted: '2' must be more than 3 numeric digits. Expression: (text.size() >= 3)
-1 cannot be converted: '-1' must be more than 3 numeric digits. Expression: (text.size() >= 3)
-10 cannot be converted: '-10' must be more than 3 numeric digits. Expression: (text.size() >= 3)
2002 cannot be converted: '2002' must have an odd number of digits. Expression: ((text.size() % 2) == 1)
-2002 cannot be converted: '-2002' must have an odd number of digits. Expression: ((text.size() % 2) == 1)
0 cannot be converted: '0' must be more than 3 numeric digits. Expression: (text.size() >= 3)</pre>
=={{header|Haskell}}==
<syntaxhighlight lang="haskell">------------------- MIDDLE THREE DIGITS ------------------
mid3 :: Int -> Either String String
mid3 n
| m < 100 = Left "too small"
| even lng = Left "even number of digits"
| otherwise = Right . take 3 $ drop ((lng - 3) `div` 2) s
where
m = abs n
s = show m
lng = length s
--------------------------- TEST -------------------------
main :: IO ()
main = do
let xs =
[ 123
, 12345
, 1234567
, 987654321
, 10001
, -10001
, -123
, -100
, 100
, -12345
, 1
, 2
, -1
, -10
, 2002
, -2002
, 0
]
w = maximum $ length . show <$> xs
(putStrLn . unlines) $
(\n ->
justifyRight w ' ' (show n) <>
" -> " <> either (concat . ("(" :) . (: [")"])) id (mid3 n)) <$>
xs
justifyRight :: Int -> Char -> String -> String
justifyRight n c = (drop . length) <*> (replicate n c <>)</syntaxhighlight>
Output:
<pre> 123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> (too small)
2 -> (too small)
-1 -> (too small)
-10 -> (too small)
2002 -> (even number of digits)
-2002 -> (even number of digits)
0 -> (too small)</pre>
=={{header|Icon}} and {{header|Unicon}}==
The following solution works in both languages.
<syntaxhighlight lang="unicon">procedure main(a)
every n := !a do write(right(n,15)," -> ",midM(n))
end
procedure midM(n,m)
/m := 3
n := abs(n)
return n ? if (*n >= m) then
if (((*n-m) % 2) = 0) then (move((*n - m)/2),move(m))
else "wrong number of digits"
else "too short"
end</syntaxhighlight>
with output:
<pre>->m3d 123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1 -10 2002 -2002 0
123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> too short
2 -> too short
-1 -> too short
-10 -> too short
2002 -> wrong number of digits
-2002 -> wrong number of digits
0 -> too short
-></pre>
=={{header|J}}==
A key issue here is that some numbers do not have a "middle 3 digits" -- either because the number is too short, or because it has an even number of digits (or both, two digit numbers).
'''Solution:'''
<
getPfxSize=: [: -:@| 3 -~ # NB. get size of prefix to drop before the 3 middle digits
getMid3=: (3 {. getPfxSize }. ,&'err') :: ('err'"_) NB. get 3 middle digits or return 'err'
getMiddle3=: getMid3@asString@:|</
'''Example:'''
<
getMiddle3 vals
123
Line 321 ⟶ 3,552:
err
err
err</
Or, expressed more concisely:<syntaxhighlight lang="j"> ({~ 2 1 0 -~ -:@>:@#) ::('err'"_)@":@| vals
123
234
345
654
000
000
123
100
100
234
err
err
err
err
err
err
err</syntaxhighlight>
=={{header|Java}}==
<
public static void main(String[] args) {
Line 350 ⟶ 3,600:
return s.substring(mid - 1, mid + 2);
}
}</
<pre>middleThreeDigits(123): 123
middleThreeDigits(12345): 234
Line 372 ⟶ 3,622:
middleThreeDigits(-2147483648): Need odd and >= 3 digits
middleThreeDigits(2147483647): Need odd and >= 3 digits</pre>
=={{header|JavaScript}}==
<syntaxhighlight lang="javascript">function middleThree(x){
var n=''+Math.abs(x); var l=n.length-1;
if(l<2||l%2) throw new Error(x+': Invalid length '+(l+1));
return n.slice(l/2-1,l/2+2);
}
[123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345,
1, 2, -1, -10, 2002, -2002, 0].forEach(function(n){
try{console.log(n,middleThree(n))}catch(e){console.error(e.message)}
});</syntaxhighlight>
<pre>123 "123"
12345 "234"
1234567 "345"
987654321 "654"
10001 "000"
-10001 "000"
-123 "123"
-100 "100"
100 "100"
-12345 "234"
1: Invalid length 1
2: Invalid length 1
-1: Invalid length 1
-10: Invalid length 2
2002: Invalid length 4
-2002: Invalid length 4
0: Invalid length 1</pre>
Or, using an option type, composing a solution from existing generic primitives, and formatting the output a little:
{{Trans|Python}}
<syntaxhighlight lang="javascript">(() => {
'use strict';
// mid3digits :: Int -> Either String String
const mid3digits = n => {
const
m = abs(n),
s = m.toString();
return 100 > m ? (
Left('Less than 3 digits')
) : even(length(s)) ? (
Left('Even digit count')
) : Right(take(3, drop(quot(length(s) - 3, 2), s)));
};
// TEST -----------------------------------------------
const main = () => {
const
xs = [
123, 12345, 1234567, 987654321, 10001, -10001, -123,
-100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0
],
w = maximum(map(x => x.toString().length, xs));
return (
unlines(map(
n => justifyRight(w, ' ', n.toString()) + ' -> ' +
either(
s => '(' + s + ')',
id,
mid3digits(n)
),
xs
))
);
};
// GENERIC FUNCTIONS ----------------------------------
// Left :: a -> Either a b
const Left = x => ({
type: 'Either',
Left: x
});
// Right :: b -> Either a b
const Right = x => ({
type: 'Either',
Right: x
});
// abs :: Num -> Num
const abs = Math.abs;
// drop :: Int -> [a] -> [a]
// drop :: Int -> Generator [a] -> Generator [a]
// drop :: Int -> String -> String
const drop = (n, xs) =>
Infinity > length(xs) ? (
xs.slice(n)
) : (take(n, xs), xs);
// either :: (a -> c) -> (b -> c) -> Either a b -> c
const either = (fl, fr, e) =>
'Either' === e.type ? (
undefined !== e.Left ? (
fl(e.Left)
) : fr(e.Right)
) : undefined;
// even :: Int -> Bool
const even = n => 0 === n % 2;
// foldl1 :: (a -> a -> a) -> [a] -> a
const foldl1 = (f, xs) =>
1 < xs.length ? xs.slice(1)
.reduce(f, xs[0]) : xs[0];
// id :: a -> a
const id = x => x;
// justifyRight :: Int -> Char -> String -> String
const justifyRight = (n, cFiller, s) =>
n > s.length ? (
s.padStart(n, cFiller)
) : s;
// Returns Infinity over objects without finite length.
// This enables zip and zipWith to choose the shorter
// argument when one is non-finite, like cycle, repeat etc
// length :: [a] -> Int
const length = xs =>
(Array.isArray(xs) || 'string' === typeof xs) ? (
xs.length
) : Infinity;
// maximum :: Ord a => [a] -> a
const maximum = xs =>
0 < xs.length ? (
foldl1((a, x) => x > a ? x : a, xs)
) : undefined;
// map :: (a -> b) -> [a] -> [b]
const map = (f, xs) => xs.map(f);
// quot :: Int -> Int -> Int
const quot = (n, m) => Math.floor(n / m);
// take :: Int -> [a] -> [a]
// take :: Int -> String -> String
const take = (n, xs) =>
'GeneratorFunction' !== xs.constructor.constructor.name ? (
xs.slice(0, n)
) : [].concat.apply([], Array.from({
length: n
}, () => {
const x = xs.next();
return x.done ? [] : [x.value];
}));
// unlines :: [String] -> String
const unlines = xs => xs.join('\n');
// MAIN ---
return main();
})();</syntaxhighlight>
{{Out}}
<pre>
123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> (Less than 3 digits)
2 -> (Less than 3 digits)
-1 -> (Less than 3 digits)
-10 -> (Less than 3 digits)
2002 -> (Even digit count)
-2002 -> (Even digit count)
0 -> (Less than 3 digits)</pre>
=={{header|jq}}==
<syntaxhighlight lang="jq">def middle3:
if . < 0 then -. else . end
| tostring as $s
| ($s | length) as $n
| if $n<3 or ($n % 2) == 0 then "invalid length: \($n)"
else (($n - 1) / 2) as $n | $s[$n - 1 : $n + 2]
end ;
(123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0)
| "\(.) => \( .|middle3 )"</syntaxhighlight>
Typescript:<syntaxhighlight lang="sh"> $ jq -r -n -f Middle_three_digits.jq
123 => 123
12345 => 234
1234567 => 345
987654321 => 654
10001 => 000
-10001 => 000
-123 => 123
-100 => 100
100 => 100
-12345 => 234
1 => invalid length: 1
2 => invalid length: 1
-1 => invalid length: 1
-10 => invalid length: 2
2002 => invalid length: 4
-2002 => invalid length: 4
0 => invalid length: 1 </syntaxhighlight>
=={{header|Julia}}==
{{works with|Julia|1.0.3}}
<syntaxhighlight lang="julia">using Printf
function middle3(n::Integer)
l = ndigits(n)
iseven(l) && error("n must have an odd number of digits")
l < 3 && error("n must have 3 digits or more")
mid = (l + 1) ÷ 2
abs(n) ÷ 10^(mid-2) % 10^3
end
for n = [123, 12345, 1234567, 987654321, 10001, -10001, -123,
-100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0]
@printf("%10d -> %s\n", n, try middle3(n) catch e e.msg end)
end</syntaxhighlight>
{{out}}
<pre> 123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> n must have 3 digits or more
2 -> n must have 3 digits or more
-1 -> n must have 3 digits or more
-10 -> n must have an odd number of digits
2002 -> n must have an odd number of digits
-2002 -> n must have an odd number of digits
0 -> n must have 3 digits or more</pre>
=={{header|K}}==
<syntaxhighlight lang="k">
/ Rosetta code - Middle three digits
/ mid3.k
mid3: {qs:$x;:[qs[0]="-";qs: 1 _ qs];:[(#qs)<3;:"small";(1+#qs)!2;:"even"];p:(-3+#qs)%2;:(|p _|p _ qs)}
</syntaxhighlight>
The output of the session:
{{out}}
<pre>
K Console - Enter \ for help
\l mid3
mid3' 123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1 -10
2002 -2002 0
("123"
"234"
"345"
"654"
"000"
"000"
"123"
"100"
"100"
"234"
"small"
"small"
"small"
"small"
"even"
"even"
"small")
</pre>
=={{header|Klingphix}}==
<syntaxhighlight lang="klingphix">include ..\Utilitys.tlhy
( 123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1 -10 2002 -2002 0 )
len [
get ( dup " : " ) lprint
abs tostr len >ps
tps 3 < ( ["too short" ?]
[ tps 2 mod ( [tps 2 / 3 slice ?] ["is even" ?] ) if]
) if
ps> drop drop
] for
" " input
</syntaxhighlight>
{{out}}
<pre>123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : too short
2 : too short
-1 : too short
-10 : too short
2002 : is even
-2002 : is even
0 : too short</pre>
=={{header|Klong}}==
<syntaxhighlight lang="k">items::[123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1 -10 2002 -2002 0]
mid3::{[d k];:[3>k::#$#x;"small":|0=k!2;"even";(-d)_(d::_(k%2)-1)_$#x]}
.p(mid3'items)</syntaxhighlight>
Output:
<pre>[123 234 345 654 000 000 123 100 100 234 small small small small even even small]</pre>
=={{header|Kotlin}}==
<syntaxhighlight lang="scala">fun middleThree(x: Int): Int? {
val s = Math.abs(x).toString()
return when {
s.length < 3 -> null // throw Exception("too short!")
s.length % 2 == 0 -> null // throw Exception("even number of digits")
else -> ((s.length / 2) - 1).let { s.substring(it, it + 3) }.toInt()
}
}
fun main(args: Array<String>) {
println(middleThree(12345)) // 234
println(middleThree(1234)) // null
println(middleThree(1234567)) // 345
println(middleThree(123))// 123
println(middleThree(123555)) //null
}</syntaxhighlight>
=={{header|Lambdatalk}}==
<syntaxhighlight lang="scheme">
{def S 123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345
1 2 -1 -10 2002 -2002 0}
-> S
{def middle3digits
{lambda {:w}
{let { {:w {abs :w}}
{:l {W.length {abs :w}}}
} {if {= {% :l 2} 0}
then has an even number of digits
else {if {< :l 3}
then has not enough digits
else {W.get {- {/ :l 2} 1} :w}
{W.get {/ :l 2} :w}
{W.get {+ {/ :l 2} 1} :w} }}}}}
-> middle3digits
{table
{S.map {lambda {:i}
{tr {td {@ style="text-align:right;"}:i:}
{td {middle3digits :i}}}}
{S}} }
->
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: has not enough digits
2: has not enough digits
-1: has not enough digits
-10: has an even number of digits
2002: has an even number of digits
-2002: has an even number of digits
0: has not enough digits
</syntaxhighlight>
=={{header|Lasso}}==
<syntaxhighlight lang="lasso">define middlethree(value::integer) => {
local(
pos_value = math_abs(#value),
stringvalue = #pos_value -> asstring,
intlength = #stringvalue -> size,
middle = integer((#intlength + 1) / 2),
prefix = string(#value) -> padleading(15)& + ': '
)
#intlength < 3 ? return #prefix + 'Error: too few digits'
not(#intlength % 2) ? return #prefix + 'Error: even number of digits'
return #prefix + #stringvalue -> sub(#middle -1, 3)
}
'<pre>'
with number in array(123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0) do {^
middlethree(#number)
'<br />'
^}
'</pre>'</syntaxhighlight>
'''Output'''
<pre> 123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: Error: too few digits
2: Error: too few digits
-1: Error: too few digits
-10: Error: too few digits
2002: Error: even number of digits
-2002: Error: even number of digits
0: Error: too few digits</pre>
=={{header|Logo}}==
<syntaxhighlight lang="logo">to middle3digits :n
if [less? :n 0] [make "n minus :n]
local "len make "len count :n
if [less? :len 3] [(throw "error [Number must have at least 3 digits])]
if [equal? 0 modulo :len 2] [(throw "error [Number must have odd number of digits])]
while [greater? count :n 3] [
make "n butlast butfirst :n
]
output :n
end
foreach [123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345
1 2 -1 -10 2002 -2002 0] [
type sentence (word ? ": char 9) runresult [if [less? count ? 7] [char 9]]
make "mid runresult [catch "error [middle3digits ?]]
print ifelse [empty? :mid] [item 2 error] [:mid]
]
bye</syntaxhighlight>
{{Output}}
<pre>123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: Number must have at least 3 digits
2: Number must have at least 3 digits
-1: Number must have at least 3 digits
-10: Number must have at least 3 digits
2002: Number must have odd number of digits
-2002: Number must have odd number of digits
0: Number must have at least 3 digits</pre>
=={{header|Lua}}==
<syntaxhighlight lang="lua">function middle_three(n)
if n < 0 then
n = -n
end
n = tostring(n)
if #n % 2 == 0 then
return "Error: the number of digits is even."
elseif #n < 3 then
return "Error: the number has less than 3 digits."
end
local l = math.floor(#n/2)
return n:sub(l, l+2)
end
-- test
do
local t = {123, 12345, 1234567, 987654321,
10001, -10001, -123, -100, 100, -12345, 1,
2, -1, -10, 2002, -2002, 0}
for _,n in pairs(t) do
print(n, middle_three(n))
end
end</syntaxhighlight>
{{out}}
<pre>123 123
12345 234
1234567 345
987654321 654
10001 000
-10001 000
-123 123
-100 100
100 100
-12345 234
1 Error: the number has less than 3 digits.
2 Error: the number has less than 3 digits.
-1 Error: the number has less than 3 digits.
-10 Error: the number is even.
2002 Error: the number is even.
-2002 Error: the number is even.
0 Error: the number has less than 3 digits.</pre>
=={{header|Maple}}==
<syntaxhighlight lang="maple">middleDigits := proc(n)
local nList, start;
nList := [seq(parse(i), i in convert (abs(n), string))];
if numelems(nList) < 3 then
printf ("%9a: Error: Not enough digits.", n);
elif numelems(nList) mod 2 = 0 then
printf ("%9a: Error: Even number of digits.", n);
else
start := (numelems(nList)-1)/2;
printf("%9a: %a%a%a", n, op(nList[start..start+2]));
end if;
end proc:
a := [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345,
1, 2, -1, -10, 2002, -2002, 0]:
for i in a do
middleDigits(i);
printf("\n");
end do;</syntaxhighlight>
{{out}}
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: Error: Not enough digits.
2: Error: Not enough digits.
-1: Error: Not enough digits.
-10: Error: Not enough digits.
2002: Error: Even number of digits.
-2002: Error: Even number of digits.
0: Error: Not enough digits.
</pre>
=={{header|Mathematica}}/{{header|Wolfram Language}}==
<syntaxhighlight lang="mathematica">middleThree[n_Integer] :=
Block[{digits = IntegerDigits[n], len},
len = Length[digits];
If[len < 3 || EvenQ[len], "number digits odd or less than 3",
len = Ceiling[len/2];
StringJoin @@ (ToString /@ digits[[len - 1 ;; len + 1]])]]
testData = {123, 12345, 1234567, 987654321, 10001, -10001, -123, -100,
100, -12345, 1, 2, -1, -10, 2002, -2002, 0};
Column[middleThree /@ testData]</syntaxhighlight>
{{out}}<pre>123
234
345
654
000
000
123
100
100
234
err: n too small
err: n too small
err: n too small
err: n too small
err: even number of digits
err: even number of digits
err: n too small</pre>
=={{header|MATLAB}} / {{header|Octave}}==
<syntaxhighlight lang="matlab">function s=middle_three_digits(a)
% http://rosettacode.org/wiki/Middle_three_digits
s=num2str(abs(a));
if ~mod(length(s),2)
s='*** error: number of digits must be odd ***';
return;
end;
if length(s)<3,
s='*** error: number of digits must not be smaller than 3 ***';
return;
end;
s = s((length(s)+1)/2+[-1:1]);</syntaxhighlight>
Test with
<syntaxhighlight lang="matlab"> x=[123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0];
for k=1:length(x); fprintf(1,'%9i:%s\n',x(k),middle_three_digits(x(k)));end;</syntaxhighlight>
Result
<pre>
123:123
12345:234
1234567:457
987654321:654
10001:000
-10001:000
-123:123
-100:100
100:100
-12345:234
1:*** error: number of digits must not be smaller than 3 ***
2:*** error: number of digits must not be smaller than 3 ***
-1:*** error: number of digits must not be smaller than 3 ***
-10:*** error: number of digits must be odd ***
2002:*** error: number of digits must be odd ***
-2002:*** error: number of digits must be odd ***
0:*** error: number of digits must not be smaller than 3 ***
</pre>
=={{header|MiniScript}}==
<syntaxhighlight lang="miniscript">middle3 = function(num)
if num < 0 then num = -num
s = str(num)
if s.len < 3 then return "Input too short"
if s.len % 2 == 0 then return "Input length not odd"
mid = (s.len + 1) / 2 - 1
return s[mid-1:mid+2]
end function
for test in [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100,
100, -12345, 1, 2, -1, -10, 2002, -2002, 0]
print test + " --> " + middle3(test)
end for</syntaxhighlight>
{{out}}
<pre>123 --> 123
12345 --> 234
1234567 --> 345
987654321 --> 654
10001 --> 000
-10001 --> 000
-123 --> 123
-100 --> 100
100 --> 100
-12345 --> 234
1 --> Input too short
2 --> Input too short
-1 --> Input too short
-10 --> Input too short
2002 --> Input length not odd
-2002 --> Input length not odd
0 --> Input too short</pre>
=={{header|МК-61/52}}==
<syntaxhighlight lang="text">П0 lg [x] 3 - x>=0 23 ИП0 1 0
/ [x] ^ lg [x] 10^x П1 / {x} ИП1
* БП 00 1 + x=0 29 ИП0 С/П 0
/</syntaxhighlight>
''Instruction:'' enter the number in the РX (on display), the result after the execution of the same. In the case of an even or less than 3 number of digits the indicator displays an error message.
=={{header|ML}}==
==={{header|mLite}}===
<syntaxhighlight lang="ocaml">
val test_array = ["123","12345","1234567","987654321","10001","~10001","~123","~100","100","~12345","1","2","~1","~10","2002","~2002","0"];
fun even (x rem 2 = 0) = true | _ = false;
fun middleThreeDigits
(h :: t, s, 1 ) = s @ " --> too small"
| (h :: t, s, 2 ) = s @ " --> has even digits"
| (h :: t, s, 3 ) where (len (h :: t) = 3) = s @ " --> " @ (implode (h :: t))
| (h :: t, s, 3 ) = (middleThreeDigits ( sub (t, 0, (len t)-1), s, 3))
| (h :: t, s, m) = if len (h :: t) < 3 then
middleThreeDigits (h :: t, s, 1)
else
if even ` len (h :: t) then
middleThreeDigits (h :: t, s, 2)
else
middleThreeDigits (h :: t, s, 3)
| s = if sub (s, 0, 1) = "~" then
middleThreeDigits (sub (explode s, 1, len s), s, 0)
else
middleThreeDigits (explode s, s, 0)
;
map (println o middleThreeDigits) test_array;</syntaxhighlight>
Output:
<pre>123 --> 123
12345 --> 234
1234567 --> 345
987654321 --> 654
10001 --> 000
~10001 --> 000
~123 --> 123
~100 --> 100
100 --> 100
~12345 --> 234
1 --> too small
2 --> too small
~1 --> too small
~10 --> too small
2002 --> has even digits
~2002 --> has even digits
0 --> too small</pre>
=={{header|MUMPS}}==
This sample shows the MUMPS code required to pass the specification.
<syntaxhighlight lang="mumps">/* MUMPS */
MID3(N) ;
N LEN,N2
S N2=$S(N<0:-N,1:N)
I N2<100 Q "NUMBER TOO SMALL"
S LEN=$L(N2)
I LEN#2=0 Q "EVEN NUMBER OF DIGITS"
Q $E(N2,LEN\2,LEN\2+2)
F I=123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345,1,2,-1,-10,2002,-2002,0 W !,$J(I,10),": ",$$MID3^MID3(I)
</syntaxhighlight>
'''Output:'''
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: NUMBER TOO SMALL
2: NUMBER TOO SMALL
-1: NUMBER TOO SMALL
-10: NUMBER TOO SMALL
2002: EVEN NUMBER OF DIGITS
-2002: EVEN NUMBER OF DIGITS
0: NUMBER TOO SMALL
</pre>
=={{header|NetRexx}}==
This sample goes the extra mile and provides a method that can display the middle N digits from the input value. To satisfy the requirements of this task, a static invocation of this general method is also provided with the value '''<tt>3</tt>''' hard coded as the digit count.
<syntaxhighlight lang="netrexx">/* NetRexx */
options replace format comments java crossref symbols nobinary
sl = '123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345' -
'1 2 -1 -10 2002 -2002 0' -
'abc 1e3 -17e-3 4004.5 12345678 9876543210' -- extras
parse arg digsL digsR .
if \digsL.datatype('w') then digsL = 3
if \digsR.datatype('w') then digsR = digsL
if digsL > digsR then digsR = digsL
loop dc = digsL to digsR
say 'Middle' dc 'characters'
loop nn = 1 to sl.words()
val = sl.word(nn)
say middleDigits(dc, val)
end nn
say
end dc
return
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method middle3Digits(val) constant
return middleDigits(3, val)
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method middleDigits(digitCt, val) constant
text = val.right(15)':'
even = digitCt // 2 == 0 -- odd or even?
select
when digitCt <= 0 then text = 'digit selection size must be >= 1'
when \val.datatype('w') then text = text 'is not a whole number'
when val.abs().length < digitCt then text = text 'has less than' digitCt 'digits'
when \even & val.abs().length // 2 == 0 then text = text 'does not have an odd number of digits'
when even & val.abs().length // 2 \= 0 then text = text 'does not have an even number of digits'
otherwise do
val = val.abs()
valL = val.length
cutP = (valL - digitCt) % 2
text = text val.substr(cutP + 1, digitCt)
end
catch NumberFormatException
text = val 'is not numeric'
end
return text
</syntaxhighlight>
'''Output:'''
<pre>
Middle 3 characters
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: has less than 3 digits
2: has less than 3 digits
-1: has less than 3 digits
-10: has less than 3 digits
2002: does not have an odd number of digits
-2002: does not have an odd number of digits
0: has less than 3 digits
abc: is not a whole number
1e3: is not a whole number
-17e-3: is not a whole number
4004.5: is not a whole number
12345678: does not have an odd number of digits
9876543210: does not have an odd number of digits
</pre>
=={{header|NewLISP}}==
<syntaxhighlight lang="newlisp">
(define (middle3 x)
(if (even? (length x))
(println "You entered " x ". I need an odd number of digits, not " (length x) ".")
(if (< (length x) 3)
(println "You entered " x ". Sorry, but I need 3 or more digits.")
(println "The middle 3 digits of " x " are " ((- (/ (- (length x) 1) 2) 1) 3 (string (abs x))) ".")
)
)
)
(map middle3 lst)
</syntaxhighlight>
'''Output:'''
<pre>
The middle 3 digits of 123 are 123.
The middle 3 digits of 12345 are 234.
The middle 3 digits of 1234567 are 345.
The middle 3 digits of 987654321 are 654.
The middle 3 digits of 10001 are 000.
The middle 3 digits of -10001 are 000.
The middle 3 digits of -123 are 123.
The middle 3 digits of -100 are 100.
The middle 3 digits of 100 are 100.
The middle 3 digits of -12345 are 234.
You entered 1. Sorry, but I need 3 or more digits.
You entered 2. Sorry, but I need 3 or more digits.
You entered -1. Sorry, but I need 3 or more digits.
You entered 10. I need an odd number of digits, not 2.
You entered 2002. I need an odd number of digits, not 4.
You entered -2002. I need an odd number of digits, not 4.
You entered 0. Sorry, but I need 3 or more digits.
</pre>
=={{header|Nim}}==
<syntaxhighlight lang="nim">proc middleThreeDigits(i: int): string =
var s = $abs(i)
if s.len < 3 or s.len mod 2 == 0:
raise newException(ValueError, "Need odd and >= 3 digits")
let mid = s.len div 2
return s[mid-1..mid+1]
const passing = @[123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345]
const failing = @[1, 2, -1, -10, 2002, -2002, 0]
for i in passing & failing:
var answer = try: middleThreeDigits(i)
except ValueError: getCurrentExceptionMsg()
echo "middleThreeDigits(", i, ") returned: ", answer</syntaxhighlight>
{{out}}
<pre>middleThreeDigits(123) returned: 123
middleThreeDigits(12345) returned: 234
middleThreeDigits(1234567) returned: 345
middleThreeDigits(987654321) returned: 654
middleThreeDigits(10001) returned: 000
middleThreeDigits(-10001) returned: 000
middleThreeDigits(-123) returned: 123
middleThreeDigits(-100) returned: 100
middleThreeDigits(100) returned: 100
middleThreeDigits(-12345) returned: 234
middleThreeDigits(1) returned: Need odd and >= 3 digits
middleThreeDigits(2) returned: Need odd and >= 3 digits
middleThreeDigits(-1) returned: Need odd and >= 3 digits
middleThreeDigits(-10) returned: Need odd and >= 3 digits
middleThreeDigits(2002) returned: Need odd and >= 3 digits
middleThreeDigits(-2002) returned: Need odd and >= 3 digits
middleThreeDigits(0) returned: Need odd and >= 3 digits</pre>
=={{header|Objeck}}==
<syntaxhighlight lang="objeck">
class Test {
function : Main(args : String[]) ~ Nil {
text := "123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0";
ins := text->Split(",");
each(i : ins) {
in := ins[i]->Trim();
IO.Console->Print(in)->Print(": ");
in := (in->Size() > 0 & in->Get(0) = '-') ? in->SubString(1, in->Size() - 1) : in;
IO.Console->PrintLine((in->Size() < 2 | in->Size() % 2 = 0) ? "Error" : in->SubString((in->Size() - 3) / 2, 3));
};
}
}</syntaxhighlight>
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: Error
2: Error
-1: Error
-10: Error
2002: Error
-2002: Error
0: Error
</pre>
=={{header|OCaml}}==
<
let middle_three_digits x =
Line 399 ⟶ 4,580:
print_endline "Should fail:";
List.iter print failing;
;;</
{{out}}
Line 425 ⟶ 4,606:
</pre>
=={{header|
<syntaxhighlight lang="oforth">: middle3
| s sz |
abs asString dup ->s size ->sz
sz 3 < ifTrue: [ "Too short" println return ]
sz isEven ifTrue: [ "Not odd number of digits" println return ]
sz 3 - 2 / 1+ dup 2 + s extract ;</syntaxhighlight>
{{out}}
<pre>
[ 123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345] map(#middle3) println
[123, 234, 345, 654, 000, 000, 123, 100, 100, 234]
[ 1, 2, -1, -10, 2002, -2002, 0 ] apply(#middle3)
Too short
Too short
Too short
Too short
Not odd number of digits
Not odd number of digits
Too short
</pre>
=={{header|PARI/GP}}==
{{works with|PARI/GP|2.6.0}}
<syntaxhighlight lang="parigp">middle(n)=my(v=digits(n));if(#v>2&&#v%2,100*v[#v\2]+10*v[#v\2+1]+v[#v\2+2],"no middle 3 digits");
apply(middle,[123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0])</syntaxhighlight>
Output:
<pre>%1 = [123, 234, 345, 654, 0, 0, 123, 100, 100, 234, "no middle 3 digits", "no middle 3 digits", "no middle 3 digits", "no middle 3 digits", "no middle 3 digits", "no middle 3 digits", "no middle 3 digits"]</pre>
If for some reason you want to see the leading digits, you can run
<syntaxhighlight lang="parigp">apply(n-> Strprintf("%03d", n), %)</syntaxhighlight>
For earlier versions <code>digits</code> can be defined as
<syntaxhighlight lang="parigp">digits(n)=eval(Vec(Str(n)))</syntaxhighlight>
or more efficiently as
<syntaxhighlight lang="parigp">digits(n)=Vec(apply(n->n-48,Vectorsmall(Str(n))))</syntaxhighlight>
=={{header|Pascal}}==
{{works with|Free Pascal}}
<syntaxhighlight lang="pascal">program Midl3dig;
{$IFDEF FPC}
{$MODE Delphi} //result /integer => Int32 aka longInt etc..
{$ELSE}
{$APPTYPE console} // Delphi
{$ENDIF}
uses
sysutils; //IntToStr
function GetMid3dig(i:NativeInt):Ansistring;
var
n,l: NativeInt;
Begin
setlength(result,0);
//n = |i| jumpless abs
n := i-((ORD(i>0)-1)AND (2*i));
//calculate digitcount
IF n > 0 then
l := trunc(ln(n)/ln(10))+1
else
l := 1;
if l<3 then Begin write('got too few digits'); EXIT; end;
If Not(ODD(l)) then Begin write('got even number of digits'); EXIT; end;
result:= copy(IntToStr(n),l DIV 2,3);
end;
const
Test : array [0..16] of NativeInt =
( 123,12345,1234567,987654321,10001,-10001,
-123,-100,100,-12345,1,2,-1,-10,2002,-2002,0);
var
i,n : NativeInt;
Begin
For i := low(Test) to High(Test) do
Begin
n := Test[i];
writeln(n:9,': ',GetMid3dig(Test[i]));
end;
end.</syntaxhighlight>
{{out}}
<pre> 123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: got too few digits
2: got too few digits
-1: got too few digits
-10: got too few digits
2002: got even number of digits
-2002: got even number of digits
0: got too few digits
</pre>
=={{header|Perl}}==
<syntaxhighlight lang="perl">#!/usr/bin/perl
use strict ;
use warnings ;
sub middlethree {
my $number = shift ;
my $testnumber = abs $number ;
my $error = "Middle 3 digits can't be shown" ;
my $numberlength = length $testnumber ;
if ( $numberlength < 3 ) {
print "$error : $number too short!\n" ;
return ;
}
if ( $numberlength % 2 == 0 ) {
print "$error : even number of digits in $number!\n" ;
return ;
}
my $middle = int ( $numberlength / 2 ) ;
print "Middle 3 digits of $number : " . substr( $testnumber , $middle - 1 , 3 ) . " !\n" ;
return ;
}
my @numbers = ( 123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345 ,
map { middlethree( $_ ) } @numbers ;
</syntaxhighlight>
{{out}}
<pre>
Middle 3 digits can't be shown : -1
Middle 3 digits can't be shown : -10
</pre>
=={{header|Phix}}==
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #008080;">procedure</span> <span style="color: #000000;">mid3</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">string</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"%d"</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">abs</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">))</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)-</span><span style="color: #000000;">3</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%10d: %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">k</span><span style="color: #0000FF;"><</span><span style="color: #000000;">0</span> <span style="color: #008080;">or</span> <span style="color: #7060A8;">and_bits</span><span style="color: #0000FF;">(</span><span style="color: #000000;">k</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)?</span><span style="color: #008000;">"error"</span><span style="color: #0000FF;">:</span><span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">k</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">+</span><span style="color: #000000;">3</span><span style="color: #0000FF;">])})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">constant</span> <span style="color: #000000;">tests</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">123</span><span style="color: #0000FF;">,</span><span style="color: #000000;">12345</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1234567</span><span style="color: #0000FF;">,</span><span style="color: #000000;">987654321</span><span style="color: #0000FF;">,</span><span style="color: #000000;">10001</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">10001</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">123</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">100</span><span style="color: #0000FF;">,</span><span style="color: #000000;">100</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">12345</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">10</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2002</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">2002</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">}</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">tests</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">mid3</span><span style="color: #0000FF;">(</span><span style="color: #000000;">tests</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">])</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: error
2: error
-1: error
-10: error
2002: error
-2002: error
0: error
</pre>
=={{header|PHP}}==
<syntaxhighlight lang="php">// 32-bit builds of PHP: Integers can be from -2147483648 to 2147483647
// 64-bit builds of PHP: Integers can be from -9223372036854775808 to 9223372036854775807
function middlethree($integer)
{
$int = (int)str_replace('-','',$integer);
$length = strlen($int);
if(is_int($int))
{
if($length >= 3)
{
if($length % 2 == 1)
{
$middle = floor($length / 2) - 1;
return substr($int,$middle, 3);
}
else
{
return 'The value must contain an odd amount of digits...';
}
}
else
{
return 'The value must contain at least three digits...';
}
}
else
{
return 'The value does not appear to be an integer...';
}
}
$numbers = array(123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0);
foreach($numbers as $nums)
{
echo $nums.' : '.middlethree($nums). '<br>';
}</syntaxhighlight>
Output:
<pre>123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : The value must contain at least three digits...
2 : The value must contain at least three digits...
-1 : The value must contain at least three digits...
-10 : The value must contain at least three digits...
2002 : The value must contain an odd amount of digits...
-2002 : The value must contain an odd amount of digits...
0 : The value must contain at least three digits...</pre>
=={{header|Picat}}==
===Prolog-style===
{{trans|Prolog}}
<syntaxhighlight lang="picat">get_middle_f1(Str) = [X,Y,Z] =>
append(Pre,[X,Y,Z],Post,Str),
length(Pre) = length(Post).</syntaxhighlight>
===List slice===
<syntaxhighlight lang="picat">get_middle_f2(Str) = Str[Mid-1..Mid+1] =>
Mid = 1 + Str.len div 2.</syntaxhighlight>
===Test===
<syntaxhighlight lang="picat">go =>
Success = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345],
Fail = [1, 2, -1, -10, 2002, -2002, 0],
All = Success ++ Fail,
test(All, get_middle_f1),
test(All, get_middle_f2).
% Test and check for exceptions
test(List,F) =>
printf("\nTesting %w:\n", F),
foreach(N in List)
catch(Middle=apply(get_middle,N,F), E, printf("%d = exception %w\n",N,E)),
if E.var() then
println([n=N,middle=Middle])
end
end,
nl.
% Check with the get_middle funcion F
get_middle(N,F) = apply(F,Str) =>
Str = N.abs().to_string(),
Len = length(Str),
if Len mod 2 = 0 then throw $not_odd_length(N)
elseif Len < 3 then throw $number_too_small(N)
end.</syntaxhighlight>
{{out}}
<pre>[n = 123,middle = 123]
[n = 12345,middle = 234]
[n = 1234567,middle = 345]
[n = 987654321,middle = 654]
[n = 10001,middle = 000]
[n = -10001,middle = 000]
[n = -123,middle = 123]
[n = -100,middle = 100]
[n = 100,middle = 100]
[n = -12345,middle = 234]
[n = 1,exception = number_too_small(1)]
[n = 2,exception = number_too_small(2)]
[n = -1,exception = number_too_small(-1)]
[n = -10,exception = not_odd_length(-10)]
[n = 2002,exception = not_odd_length(2002)]
[n = -2002,exception = not_odd_length(-2002)]
[n = 0,exception = number_too_small(0)]</pre>
=={{header|PicoLisp}}==
<syntaxhighlight lang="picolisp">(de middle3digits (N)
(let (Lst (chop (abs N)) Len (length Lst))
(tab (10 -2 -30)
N
":"
(cond
((> 3 Len) "not enough digits")
((bit? 1 Len)
(head 3 (nth Lst (/ Len 2))) )
(T "even number of digits") ) ) ) )</syntaxhighlight>
Test:
<syntaxhighlight lang="picolisp">(mapc middle3digits
(123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345
1 2 -1 -10 2002 -2002 0 ) )</syntaxhighlight>
Output:
<pre> 123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: not enough digits
2: not enough digits
-1: not enough digits
-10: not enough digits
2002: even number of digits
-2002: even number of digits
0: not enough digits</pre>
=={{header|Pike}}==
{{trans|PHP}}
<syntaxhighlight lang="pike">string middlethree(int i) {
i = abs(i);
int length = sizeof((string)i);
if(length >= 3) {
if(length % 2 == 1) {
int middle = (int)floor(length / 2) - 1;
return(((string)i)[middle..middle+2]);
}
else {
return "The value must contain an odd amount of digits...";
}
}
else {
return "The value must contain at least three digits...";
}
}
int main() {
array(int) numbers = ({123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0});
foreach(numbers, int nums) {
write((string)nums + " : " + middlethree(nums) + "\n");
}
return 0;
}</syntaxhighlight>
{{out}}
<pre>123 : 123
12345 : 234
1234567 : 345
987654321 : 654
10001 : 000
-10001 : 000
-123 : 123
-100 : 100
100 : 100
-12345 : 234
1 : The value must contain at least three digits...
2 : The value must contain at least three digits...
-1 : The value must contain at least three digits...
-10 : The value must contain at least three digits...
2002 : The value must contain an odd amount of digits...
-2002 : The value must contain an odd amount of digits...
0 : The value must contain at least three digits...</pre>
=={{header|PL/I}}==
<syntaxhighlight lang="pl/i">
middle: procedure options (main); /* 29 October 2013 */
declare n fixed (15);
declare s character (25) varying;
declare in file input;
open file (in) title ('/MIDDLE.DAT,type(text),recsize(100)');
on endfile (in) stop;
do forever;
get file (in) list (n); put skip list (n);
n = abs(n);
s = trim(n);
if length(s) < 3 then put list ('not possible');
else if mod(length(s), 2) = 0 then put list ('not possible');
else
do;
do while (length(s) > 3);
s = substr(s, 2, length(s)-2);
end;
put list ('The middle three digits are: ' || s);
end;
end;
end middle;
</syntaxhighlight>
Output:
<pre>
123 The middle three digits are: 123
12345 The middle three digits are: 234
1234567 The middle three digits are: 345
987654321 The middle three digits are: 654
10001 The middle three digits are: 000
-10001 The middle three digits are: 000
-123 The middle three digits are: 123
-100 The middle three digits are: 100
100 The middle three digits are: 100
-123451 not possible
2 not possible
-1 not possible
-10 not possible
2002 not possible
-2002 not possible
0 not possible
</pre>
=={{header|Plain English}}==
<syntaxhighlight lang="plainenglish">To run:
Start up.
Test 123.
Test 12345.
Test 1234567.
Test 987654321.
Test 10001.
Test -10001.
Test -123.
Test -100.
Test 100.
Test -12345.
Test 1.
Test 2.
Test -1.
Test -10.
Test 2002.
Test -2002.
Test 0.
Wait for the escape key.
Shut down.
To get the middle three digits of a number giving a string:
Privatize the number.
De-sign the number.
Convert the number to the string.
If the string's length is less than 3, put "Number has fewer than three digits" into the string; exit.
If the string's length is even, put "Number has no middle" into the string; exit.
Put the string's length divided by 2 into a midpoint number.
Slap a substring on the string.
Put the substring's first plus the midpoint minus 1 into the substring's first.
Put the substring's first plus 2 into the substring's last.
Put the substring into the string.
To test a number:
Get the middle three digits of the number giving a string.
Write "" then the number then " -> " then the string on the console.</syntaxhighlight>
{{out}}
<pre>
123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> Number has fewer than three digits
2 -> Number has fewer than three digits
-1 -> Number has fewer than three digits
-10 -> Number has fewer than three digits
2002 -> Number has no middle
-2002 -> Number has no middle
0 -> Number has fewer than three digits
</pre>
=={{header|PowerShell}}==
<syntaxhighlight lang="powershell">function middle3($inp){
$str = [Math]::abs($inp)
$leng = "$str".length
if ($leng -lt 3){
Write-host $inp": [ERROR] too short."
Return
}
if (($leng % 2) -eq 0){
Write-host $inp": [ERROR] even number of digits."
} else {
$trimmer = ($leng - 3) / 2
$ans = "$str".subString($trimmer,3)
Write-host $inp": $ans"
}
Return
}
$sample = 123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0
foreach ($x in $sample){middle3 $x}</syntaxhighlight>
{{Out}}
<pre>123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: [ERROR] too short.
2: [ERROR] too short.
-1: [ERROR] too short.
-10: [ERROR] too short.
2002: [ERROR] even number of digits.
-2002: [ERROR] even number of digits.
0: [ERROR] too short.</pre>
=={{header|Prolog}}==
{{works with|SWI-Prolog|6}}
<syntaxhighlight lang="prolog">
middle_3_digits(Number, [D1,D2,D3]) :-
verify_middle_3_able(Number, Digits),
append(FrontDigits, [D1,D2,D3| BackDigits], Digits),
same_length(FrontDigits, BackDigits).
verify_middle_3_able(Number, Digits) :-
must_be(number, Number),
AbsNumber is abs(Number),
number_chars(AbsNumber, Digits),
length(Digits, NumDigits),
( 3 > NumDigits -> domain_error('at least 3 digits', Number)
; 0 is NumDigits mod 2 -> domain_error('odd number of digits', Number)
; true
).
</syntaxhighlight>
Test code:
<syntaxhighlight lang="prolog">
test_correct :-
TestCases = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345],
foreach( ( member(TestCase, TestCases),
middle_3_digits(TestCase, Result) ),
format('Middle 3 digits of ~w ~30|: ~w~n', [TestCase, Result])
).
</syntaxhighlight>
Testing correct inputs:
<pre>
?- test_correct.
Middle 3 digits of 123 : [1,2,3]
Middle 3 digits of 12345 : [2,3,4]
Middle 3 digits of 1234567 : [3,4,5]
Middle 3 digits of 987654321 : [6,5,4]
Middle 3 digits of 10001 : [0,0,0]
Middle 3 digits of -10001 : [0,0,0]
Middle 3 digits of -123 : [1,2,3]
Middle 3 digits of -100 : [1,0,0]
Middle 3 digits of 100 : [1,0,0]
Middle 3 digits of -12345 : [2,3,4]
true.
</pre>
Errors
<pre>
?- middle_3_digits(1, S).
ERROR: Domain error: `at least 3 digits' expected, found `1'
?- middle_3_digits(2, S).
ERROR: Domain error: `at least 3 digits' expected, found `2'
?- middle_3_digits(-1, S).
ERROR: Domain error: `at least 3 digits' expected, found `-1'
?- middle_3_digits(-10, S).
ERROR: Domain error: `at least 3 digits' expected, found `-10'
?- middle_3_digits(2002, S).
ERROR: Domain error: `odd number of digits' expected, found `2002'
?- middle_3_digits(-2002, S).
ERROR: Domain error: `odd number of digits' expected, found `-2002'
?- middle_3_digits(0, S).
ERROR: Domain error: `at least 3 digits' expected, found `0'
</pre>
=={{header|Python}}==
===Procedural===
<syntaxhighlight lang="python">>>> def middle_three_digits(i):
s = str(abs(i))
length = len(s)
Line 492 ⟶ 5,239:
middle_three_digits(-2002) returned: AssertionError('Need odd and >= 3 digits',)
middle_three_digits(0) returned: AssertionError('Need odd and >= 3 digits',)
>>> </
===Composition of pure functions===
Using a composable option type as an alternative to error handling:
{{Trans|Haskell}}
<syntaxhighlight lang="python">'''Middle 3 digits'''
# mid3digits :: Int -> Either String String
def mid3digits(n):
'''Either the middle three digits,
or an explanatory string.'''
m = abs(n)
s = str(m)
return Left('Less than 3 digits') if (100 > m) else (
Left('Even digit count') if even(len(s)) else Right(
s[(len(s) - 3) // 2:][0:3]
)
)
# TEST ----------------------------------------------------
def main():
'''Test'''
def bracketed(x):
return '(' + str(x) + ')'
print(
tabulated('Middle three digits, where defined:\n')(str)(
either(bracketed)(str)
)(mid3digits)([
123, 12345, 1234567, 987654321, 10001, -10001, -123,
-100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0
])
)
# GENERIC -------------------------------------------------
# Left :: a -> Either a b
def Left(x):
'''Constructor for an empty Either (option type) value
with an associated string.'''
return {'type': 'Either', 'Right': None, 'Left': x}
# Right :: b -> Either a b
def Right(x):
'''Constructor for a populated Either (option type) value'''
return {'type': 'Either', 'Left': None, 'Right': x}
# compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
def compose(g):
'''Function composition.'''
return lambda f: lambda x: g(f(x))
# either :: (a -> c) -> (b -> c) -> Either a b -> c
def either(fl):
'''The application of fl to e if e is a Left value,
or the application of fr to e if e is a Right value.'''
return lambda fr: lambda e: fl(e['Left']) if (
None is e['Right']
) else fr(e['Right'])
# even :: Int -> Bool
def even(x):
'''Is x even ?'''
return 0 == x % 2
# tabulated :: String -> (b -> String) -> (a -> b) -> [a] -> String
def tabulated(s):
'''Heading -> x display function -> fx display function ->
f -> value list -> tabular string.'''
def go(xShow, fxShow, f, xs):
w = max(map(compose(len)(str), xs))
return s + '\n' + '\n'.join(
xShow(x).rjust(w, ' ') + ' -> ' + fxShow(f(x)) for x in xs
)
return lambda xShow: lambda fxShow: lambda f: lambda xs: go(
xShow, fxShow, f, xs
)
if __name__ == '__main__':
main()</syntaxhighlight>
{{Out}}
<pre>Middle three digits, where defined:
123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> (Less than 3 digits)
2 -> (Less than 3 digits)
-1 -> (Less than 3 digits)
-10 -> (Less than 3 digits)
2002 -> (Even digit count)
-2002 -> (Even digit count)
0 -> (Less than 3 digits)</pre>
=={{header|Quackery}}==
<syntaxhighlight lang="quackery"> [ 1 & not ] is even ( n --> b )
[ over size -
space swap of
swap join ] is justify ( $ n --> $ )
[ abs number$
dup size dup 3 < iff
[ 2drop $ "too few digits" ]
done
dup even iff
[ 2drop $ "even digit count" ]
done
dup 3 = iff
drop done
3 - 2 /
tuck split nip
swap negate split drop ] is middle3 ( n --> $ )
' [ 123 12345 1234567
987654321 10001 -10001
-123 -100 100 -12345 1
2 -1 -10 2002 -2002 0 ]
witheach
[ dup number$ 9 justify echo$
say " --> "
middle3 echo$ cr ]</syntaxhighlight>
{{out}}
<pre> 123 --> 123
12345 --> 234
1234567 --> 345
987654321 --> 654
10001 --> 000
-10001 --> 000
-123 --> 123
-100 --> 100
100 --> 100
-12345 --> 234
1 --> too few digits
2 --> too few digits
-1 --> too few digits
-10 --> too few digits
2002 --> even digit count
-2002 --> even digit count
0 --> too few digits</pre>
=={{header|Racket}}==
<syntaxhighlight lang="scheme">#lang racket
(define (middle x)
(cond
[(negative? x) (middle (- x))]
[(< x 100) "error: number too small"]
[else
(define s (number->string x))
(define l (string-length s))
(cond [(even? l) "error: number has even length"]
[else (define i (quotient l 2))
(substring s (- i 1) (+ i 2))])]))
(map middle (list 123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345))
(map middle (list 1 2 -1 -10 2002 -2002 0))</syntaxhighlight>
The output:
<syntaxhighlight lang="scheme">'("123" "234" "345" "654" "000" "000" "123" "100" "100" "234")
'("error: number too small" "error: number too small" "error: number too small" "error: number too small"
"error: number has even length" "error: number has even length" "error: number too small")</syntaxhighlight>
=={{header|Raku}}==
(formerly Perl 6)
<syntaxhighlight lang="raku" line>sub middle-three($n) {
given $n.abs {
when .chars < 3 { "$n is too short" }
when .chars %% 2 { "$n has an even number of digits" }
default { "The three middle digits of $n are: ", .substr: (.chars - 3)/2, 3 }
}
}
say middle-three($_) for <
123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345
1 2 -1 -10 2002 -2002 0
>;</syntaxhighlight>
{{out}}
<pre>The three middle digits of 123 are: 123
The three middle digits of 12345 are: 234
The three middle digits of 1234567 are: 345
The three middle digits of 987654321 are: 654
The three middle digits of 10001 are: 000
The three middle digits of -10001 are: 000
The three middle digits of -123 are: 123
The three middle digits of -100 are: 100
The three middle digits of 100 are: 100
The three middle digits of -12345 are: 234
1 is too short
2 is too short
-1 is too short
-10 is too short
2002 has an even number of digits
-2002 has an even number of digits
0 is too short</pre>
It is also possible to write a regular expression with a code assertion:
<syntaxhighlight lang="raku" line>for [\~] ^10 { say "$_ => $()" if m/^^(\d+) <(\d**3)> (\d+) $$ <?{ $0.chars == $1.chars}> / }</syntaxhighlight>
{{out}}
<pre>01234 => 123
0123456 => 234
012345678 => 345</pre>
=={{header|REXX}}==
===version 1===
<syntaxhighlight lang="rexx">/* REXX ***************************************************************
* 03.02.2013 Walter Pachl
* 19.04.2013 mid 3 is now a function returning the middle 3 digits
* or an error indication
**********************************************************************/
sl='123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345',
Line 502 ⟶ 5,473:
Do While sl<>'' /* loop through test values */
Parse Var sl s sl /* pick next value */
End
Exit
mid3: Procedure
Parse arg d /* take the argument */
Select /* first test for valid input */
When datatype(d)<>'NUM' Then
When pos('E',translate(d))>0 Then
When length(abs(d))<3 Then
When length(abs(d))//2<>1 Then
Otherwise Do /* input is ok */
dx=abs(d) /* get rid of optional sign */
ld=length(dx) /* length of digit string */
z=(ld-3)/2 /* number of digits to cut */
End
End
Return res</syntaxhighlight>
Output:
<pre>
Line 547 ⟶ 5,515:
</pre>
==
A premise: '''12.3e2''' is an integer (regardless of how it's displayed).
<br>So is the value of a '''googol''' and a '''googolplex'''.
<br><br>This REXX version is limited to numbers whose length is <big>≤</big> 100,000 decimal digits.
<br>(The decimal digits limit is defined via the '''numeric digits''' statement in the first line of the subroutine/procedure.)
<syntaxhighlight lang="rexx">/*REXX program returns the three middle digits of a decimal number (or an error msg).*/
n= '123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345',
'+123 0123 2 -1 -10 2002 -2002 0 abc 1e3 -17e-3 1234567.',
1237654.00 1234567890123456789012345678901234567890123456789012345678901234567
do j=1 for words(n); #=word(n,j) /* [↓] format number for pretty output*/
say 'middle 3 digits of' right(#, max(15, length(#) ) ) "──►" middle3(#)
end /*j*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
middle3: procedure; parse arg x; numeric digits 1e6; er=' ***error*** '
if datatype(x,'N') then x=abs(x)/1; L=length(x) /*use abs value; get length*/
if \datatype(x,'W') then return er "argument isn't an integer."
if L<3 then return er "argument is less than three digits."
if L//2==0 then return er "argument isn't an odd number of digits."
return substr(x, (L-3)%2+1, 3)</syntaxhighlight>
'''output'''
<pre>
middle 3 digits of 123 ──► 123
middle 3 digits of 12345 ──► 234
middle 3 digits of 1234567 ──► 345
middle 3 digits of 987654321 ──► 654
middle 3 digits of 10001 ──► 000
middle 3 digits of -10001 ──► 000
middle 3 digits of -123 ──► 123
middle 3 digits of -100 ──► 100
middle 3 digits of 100 ──► 100
middle 3 digits of -12345 ──► 234
middle 3 digits of +123 ──► 123
middle 3 digits of 0123 ──► 123
middle 3 digits of 2 ──► ***error*** argument is less than three digits.
middle 3 digits of -1 ──► ***error*** argument is less than three digits.
middle 3 digits of -10 ──► ***error*** argument is less than three digits.
middle 3 digits of 2002 ──► ***error*** argument isn't an odd number of digits.
middle 3 digits of -2002 ──► ***error*** argument isn't an odd number of digits.
middle 3 digits of 0 ──► ***error*** argument is less than three digits.
middle 3 digits of abc ──► ***error*** argument isn't an integer.
middle 3 digits of 1e3 ──► ***error*** argument isn't an odd number of digits.
middle 3 digits of -17e-3 ──► ***error*** argument isn't an integer.
middle 3 digits of 1234567. ──► 345
middle 3 digits of 1237654.00 ──► 376
middle 3 digits of 1234567890123456789012345678901234567890123456789012345678901234567 ──► 345
</pre>
=={{header|Ring}}==
<syntaxhighlight lang="ring">
n = 1234567
middle(n)
func middle nr
mnr = floor(len(string(nr))/2)
lennr = len(string(nr))
if lennr = 3 see "" + nr + nl
but lennr < 3 see "Number must have at least three digits"
but lennr%2=0 see "Number must have an odd number of digits"
else cnr = substr(string(nr),mnr,3) see cnr + nl ok
</syntaxhighlight>
=={{header|RPL}}==
Staying in the real world: no number/string conversion, -1 is returned if input is invalid.
{{works with|Halcyon Calc|4.2.7}}
≪ ABS DUP XPON
'''IF''' DUP 2 < OVER 2 MOD OR
'''THEN''' DROP2 -1
'''ELSE''' 2 / 1 - ALOG / IP 1000 MOD
'''END'''
≫ '<span style="color:blue">→M3D</span>' STO
≪ { 123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 -10 2002}
→ tl
≪ { }
1 tl SIZE '''FOR''' j
tl j GET <span style="color:blue">→M3D</span> +
'''NEXT'''
≫ ≫ EVAL
{{out}}
<pre>
1: { 123 234 345 654 0 0 123 100 100 234 -1 -1 }
</pre>
=={{header|Ruby}}==
<syntaxhighlight lang="ruby">def middle_three_digits(num)
# minus sign doesn't factor into digit count,
# and calling #abs acts as a duck-type assertion
num = num.abs
# convert to string and find length
length = (str = num.to_s).length
# check validity
raise ArgumentError, "Number must have at least three digits" if length < 3
raise ArgumentError, "Number must have an odd number of digits" if length.even?
return str[length/2 - 1, 3].to_i
end</syntaxhighlight>
Testing program:
<syntaxhighlight lang="ruby">samples = [
123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345,
1, 2, -1, -10, 2002, -2002, 0
]
left_column_width = samples.map { |n| n.to_s.length }.max
samples.each do |n|
end</
{{out}}
<pre>
123: 123
12345: 234
1234567: 345
Line 599 ⟶ 5,655:
=={{header|Rust}}==
<
let s: String =
let len = s.len();
if len < 3 {
Err(
} else if len % 2 == 0 {
Err(
} else {
Ok(s
}
}
fn print_result(x:
match middle_three_digits(x) {
Ok(
Err(
}
}
Line 622 ⟶ 5,678:
let passing = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345];
let failing = [1, 2, -1, -10, 2002, -2002, 0];
for i in passing.
print_result(*i);
}
for i in failing.
print_result(*i);
}
}</
{{Out}}
<pre>middle_three_digits(123) returned: Success, 123
Line 649 ⟶ 5,705:
middle_three_digits(-2002) returned: Failure, Even number of digits
middle_three_digits(0) returned: Failure, Too short</pre>
=={{header|S-lang}}==
<pre>Educational Notes:
1) Array-style string manipulations (e.g. as = as[[1:]] ) always use bytes,
not UTF-8 characters. As digits and '-' are all ASCII, all is copacetic.
2) The task doesn't require 64-bit integer support, but I added it, dependant
on whether the S-Lang library compile supports them, which it generally
does. [Main exception would be the current downloadable/installable MS-Win
version of the Jed editor.]
3) S-Lang functions peel arguments off right-to-left, opposite of many
languages. To align the order with other solutions, I enclosed the
parameters in a list. One alternative would have been for m3() to call
_stk_reverse(_NARGS), then pop each arg directly off the stack. Or of
course just list the numbers backwards.
</pre>
<syntaxhighlight lang="s-lang">
define m3(i)
{
variable s = string(i), sabs = s, l;
if (sabs[0] == '-')
sabs = sabs[[1:]];
l = strlen(sabs);
if (l < 3)
print(sprintf("%s doesn't have enough digits", s));
else if (l & 1) {
variable st = (l-3) >> 1;
print(sprintf("%13s: %s", s, sabs[[st:st+2]]));
}
else
print(sprintf("%s has an even number of digits", s));
}
define middle_3(lst)
{
foreach (lst)
m3( () );
}
middle_3( { 123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345,
#ifexists Int64_Type
6644221335577ll, -11122588999ll,
#endif
1, 2, -1, -10, 2002, -2002, 0 } );
</syntaxhighlight>
{{out}}<pre>
" 123: 123"
" 12345: 234"
" 1234567: 345"
" 987654321: 654"
" 10001: 000"
" -10001: 000"
" -123: 123"
" -100: 100"
" 100: 100"
" -12345: 234"
"6644221335577: 213"
" -11122588999: 258"
"1 doesn't have enough digits"
"2 doesn't have enough digits"
"-1 doesn't have enough digits"
"-10 doesn't have enough digits"
"2002 has an even number of digits"
"-2002 has an even number of digits"
"0 doesn't have enough digits"
</pre>
=={{header|Scala}}==
<syntaxhighlight lang="scala">/**
* Optionally return the middle three digits of an integer.
*
* @example List(123,12345,-789,1234,12) flatMap (middleThree(_)), returns: List(123, 234, 789)
*/
def middleThree( s:Int ) : Option[Int] = s.abs.toString match {
case v if v.length % 2 == 0 => None // Middle three is undefined for even lengths
case v if v.length < 3 => None
case v =>
val i = (v.length / 2) - 1
Some( v.substring(i,i+3).toInt )
}
// A little test...
val intVals = List(123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345,1,2,-1,-10,2002,-2002,0)
intVals map (middleThree(_)) map {
case None => "No middle three"
case Some(v) => "%03d".format(v) // Format the value, force leading zeroes
} mkString("\n")
</syntaxhighlight>
{{out}}
<pre>123
234
345
654
000
000
123
100
100
234
No middle three
No middle three
No middle three
No middle three
No middle three
No middle three
No middle three
</pre>
=={{header|sed}}==
<syntaxhighlight lang="sed">h
s/^[-+]\{0,1\}0*\([1-9]\([0-9][0-9]\)\{1,\}\)$/\1/
t l
s/$/ -> error!/
b
:l
s/.\(.\{3,\}\)./\1/
t l
x
G
s/\n/ -> /</syntaxhighlight>
{{out}}
<pre>
$ printf "%s\n" -12345 -10001 -2002 -123 -100 -10 -1 0 1 2 100 123 2002 10001 12345 1234567 987654321 | sed -f middle_three_digits.sed
-12345 -> 234
-10001 -> 000
-2002 -> error!
-123 -> 123
-100 -> 100
-10 -> error!
-1 -> error!
0 -> error!
1 -> error!
2 -> error!
100 -> 100
123 -> 123
2002 -> error!
10001 -> 000
12345 -> 234
1234567 -> 345
987654321 -> 654
</pre>
=={{header|Seed7}}==
<syntaxhighlight lang="seed7">$include "seed7_05.s7i";
const func string: middle3 (in integer: number) is func
result
var string: middle3 is "";
begin
middle3 := str(abs(number));
if not odd(length(middle3)) or length(middle3) < 3 then
middle3 := "error";
else
middle3 := middle3[succ((length(middle3) - 3) div 2) len 3];
end if;
end func;
const proc: main is func
local
var integer: number is 0;
var string: mid3 is "";
begin
for number range [] (123, 12345, 1234567, 987654321, 10001, -10001, -123,
-100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0) do
writeln(number <& ": " <& middle3(number));
end for;
end func;</syntaxhighlight>
{{out}}
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: error
2: error
-1: error
-10: error
2002: error
-2002: error
0: error
</pre>
=={{header|SenseTalk}}==
As a People Oriented Programming language, SenseTalk treats values in a fluid fashion. So although the calls to the middle3Digits handler pass an integer as the parameter, the handler itself treats the value as text, looking for occurrences of the text pattern <digit> in it. Similarly, the variable 'output' is initially set to a number, then becomes a text value when the middle digits are put into it at character position 15.
<syntaxhighlight lang="sensetalk">set inputs to [123, 12345, 1234567, 987654321,
10001, -10001, -123, -100, 100, -12345,
1, 2, -1, -10, 2002, -2002, 0]
repeat with each num in inputs
put num into output
put middle3digits of num into character 15 of output -- will autofill with "."s
put output
end repeat
to handle middle3digits of number
put every occurrence of <digit> in number into digits
if the number of items in digits is less than 3 then return "Error: too few digits"
if the number of items in digits is an even number then return "Error: even number of digits"
repeat while the number of items in digits is greater than 3
delete the first item of digits
delete the last item of digits
end repeat
return digits joined by empty
end middle3digits
</syntaxhighlight>
{{out}}
<pre>
123...........123
12345.........234
1234567.......345
987654321.....654
10001.........000
-10001........000
-123..........123
-100..........100
100...........100
-12345........234
1.............Error: too few digits
2.............Error: too few digits
-1............Error: too few digits
-10...........Error: too few digits
2002..........Error: even number of digits
-2002.........Error: even number of digits
0.............Error: too few digits
</pre>
=={{header|Sidef}}==
{{trans|Raku}}
<syntaxhighlight lang="ruby">func middle_three(n) {
var l = n.len
if (l < 3) {
"#{n} is too short"
} elsif (l.is_even) {
"#{n} has an even number of digits"
} else {
"The three middle digits of #{n} are: " + n.digits.slice((l-3)/2).first(3).flip.join
}
}
var nums = %n(
123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345
1 2 -1 -10 2002 -2002 0
)
nums.each { say middle_three(_) }</syntaxhighlight>
{{out}}
<pre>
The three middle digits of 123 are: 123
The three middle digits of 12345 are: 234
The three middle digits of 1234567 are: 345
The three middle digits of 987654321 are: 654
The three middle digits of 10001 are: 000
The three middle digits of -10001 are: 000
The three middle digits of -123 are: 123
The three middle digits of -100 are: 100
The three middle digits of 100 are: 100
The three middle digits of -12345 are: 234
1 is too short
2 is too short
-1 is too short
-10 is too short
2002 has an even number of digits
-2002 has an even number of digits
0 is too short
</pre>
=={{header|SQL}}==
<syntaxhighlight lang="sql">;WITH DATA
AS (SELECT CAST(ABS(NUMBER) AS NVARCHAR(MAX)) charNum,
NUMBER,
LEN(CAST(ABS(NUMBER) AS NVARCHAR(MAX))) LcharNum
FROM TABLE1)
SELECT CASE
WHEN ( LCHARNUM >= 3
AND LCHARNUM % 2 = 1 ) THEN SUBSTRING(CHARNUM, LCHARNUM / 2, 3)
ELSE 'Error!'
END Output,
NUMBER Input
FROM DATA </syntaxhighlight>
<pre>
| OUTPUT | INPUT |
|--------|-----------|
| 123 | 123 |
| 234 | 12345 |
| 345 | 1234567 |
| 654 | 987654321 |
| 000 | 10001 |
| 000 | -10001 |
| 123 | -123 |
| 100 | -100 |
| 100 | 100 |
| 234 | -12345 |
</pre>
<pre>
| OUTPUT | INPUT |
|--------|-------|
| Error! | 1 |
| Error! | 2 |
| Error! | -1 |
| Error! | -10 |
| Error! | 2002 |
| Error! | -2002 |
| Error! | 0 |
</pre>
=={{header|Swift}}==
<syntaxhighlight lang="swift">var num:Int = \\enter your number here
if num<0{num = -num}
var numArray:[Int]=[]
while num>0{
var temp:Int=num%10
numArray.append(temp)
num=num/10
}
var i:Int=numArray.count
if i<3||i%2==0{
print("Invalid Input")
}
else{
i=i/2
print("\(numArray[i+1]),\(numArray[i]),\(numArray[i-1])")
}</syntaxhighlight>
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: Invalid Input
2: Invalid Input
-1: Invalid Input
-10: Invalid Input
2002: Invalid Input
-2002: Invalid Input
0: Invalid Input
</pre>
=={{header|Tcl}}==
<syntaxhighlight lang="tcl">proc middleThree n {
if {$n < 0} {
set n [expr {-$n}]
}
set idx [expr {[string length $n] - 2}]
if {$idx % 2 == 0} {
error "no middle three digits: input is of even length"
}
if {$idx < 1} {
error "no middle three digits: insufficient digits"
}
set idx [expr {$idx / 2}]
string range $n $idx [expr {$idx+2}]
}</syntaxhighlight>
Demonstrating:
<syntaxhighlight lang="tcl">foreach n {
123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345
1 2 -1 -10 2002 -2002 0
} {
if {[catch {
set mid [middleThree $n]
} msg]} then {
puts "error for ${n}: $msg"
} else {
puts "found for ${n}: $mid"
}
}</syntaxhighlight>
{{out}}
<pre>
found for 123: 123
found for 12345: 234
found for 1234567: 345
found for 987654321: 654
found for 10001: 000
found for -10001: 000
found for -123: 123
found for -100: 100
found for 100: 100
found for -12345: 234
error for 1: no middle three digits: insufficient digits
error for 2: no middle three digits: insufficient digits
error for -1: no middle three digits: insufficient digits
error for -10: no middle three digits: input is of even length
error for 2002: no middle three digits: input is of even length
error for -2002: no middle three digits: input is of even length
error for 0: no middle three digits: insufficient digits
</pre>
=={{header|TI SR-56}}==
{| class="wikitable"
|+ Texas Instruments SR-56 Program Listing for "Middle three digits"
|-
! Display !! Key !! Display !! Key !! Display !! Key !! Display !! Key
|-
| 00 28 || <nowiki>*|x|</nowiki> || 25 54 || / || 50 || || 75 ||
|-
| 01 33 || STO || 26 02 || 2 || 51 || || 76 ||
|-
| 02 01 || 1 || 27 74 || - || 52 || || 77 ||
|-
| 03 18 || *log || 28 01 || 1 || 53 || || 78 ||
|-
| 04 29 || *Int || 29 53 || ) || 54 || || 79 ||
|-
| 05 20 || *1/x || 30 19 || *10^x || 55 || || 80 ||
|-
| 06 20 || *1/x || 31 94 || = || 56 || || 81 ||
|-
| 07 33 || STO || 32 29 || *Int || 57 || || 82 ||
|-
| 08 02 || 2 || 33 54 || / || 58 || || 83 ||
|-
| 09 54 || / || 34 01 || 1 || 59 || || 84 ||
|-
| 10 02 || 2 || 35 00 || 0 || 60 || || 85 ||
|-
| 11 94 || = || 36 00 || 0 || 61 || || 86 ||
|-
| 12 12 || INV || 37 00 || 0 || 62 || || 87 ||
|-
| 13 29 || *Int || 38 94 || = || 63 || || 88 ||
|-
| 14 74 || - || 39 12 || INV || 64 || || 89 ||
|-
| 15 92 || . || 40 29 || *Int || 65 || || 90 ||
|-
| 16 05 || 5 || 41 64 || * || 66 || || 91 ||
|-
| 17 94 || = || 42 01 || 1 || 67 || || 92 ||
|-
| 18 20 || *1/x || 43 00 || 0 || 68 || || 93 ||
|-
| 19 34 || RCL || 44 00 || 0 || 69 || || 94 ||
|-
| 20 01 || 1 || 45 00 || 0 || 70 || || 95 ||
|-
| 21 54 || / || 46 94 || = || 71 || || 96 ||
|-
| 22 52 || ( || 47 41 || R/S || 72 || || 97 ||
|-
| 23 34 || RCL || 48 || || 73 || || 98 ||
|-
| 24 02 || 2 || 49 || || 74 || || 99 ||
|}
Asterisk denotes 2nd function key.
{| class="wikitable"
|+ Register allocation
|-
| 0: Unused || 1: Number || 2: Log || 3: Unused || 4: Unused
|-
| 5: Unused || 6: Unused || 7: Unused || 8: Unused || 9: Unused
|}
Annotated listing:
<syntaxhighlight lang="text">
*|x| STO 1 // Number := |input|
*log *Int // #Digits - 1
*1/x *1/x // Divide by zero if 1-digit number
STO 2 // Log := #Digits - 1
/ 2 = INV *Int - . 5 = *1/x // Divide by zero if #Digits is even
RCL 1 / ( RCL 2 / 2 - 1 ) *10^x = // Shift appropriately
*Int / 1 0 0 0 = INV *Int * 1 0 0 0 = // Take the middle 3 digits
R/S // End
</syntaxhighlight>
'''Usage:'''
Enter the number and then press RST R/S. A flashing number indicates an error.
{{in}}
987654321 RST R/S
{{out}}
After about two seconds, '''654''' will appear on the screen.
{{in}}
12345 +/- RST R/S
{{out}}
After about two seconds, '''234''' will appear on the screen.
{{in}}
5 RST R/S
{{out}}
A flashing 9.999999999 99 appears on the screen indicating an error.
=={{header|UNIX Shell}}==
{{works with|Bourne Again Shell}}
{{works with|Korn Shell|93}}
{{works with|Z Shell}}
<syntaxhighlight lang="bash">function middle3digits
{
typeset -i n="${1#-}"
typeset -i l=${#n}
if (( l < 3 )); then
echo >&2 "$1 has less than 3 digits"
return 1
elif (( l % 2 == 0 )); then
echo >&2 "$1 has an even number of digits"
return 1
else
echo ${n:$((l/2-1)):3}
return 0
fi
}
# test
testdata=(123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1
-10 2002 -2002 0)
for n in ${testdata[@]}; do
printf "%10d: " $n
middle3digits "$n"
done</syntaxhighlight>
Output: <pre> 123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: 1 has less than 3 digits
2: 2 has less than 3 digits
-1: -1 has less than 3 digits
-10: -10 has less than 3 digits
2002: 2002 has an even number of digits
-2002: -2002 has an even number of digits
0: 0 has less than 3 digits</pre>
=={{header|VBA}}==
<syntaxhighlight lang="vb">
Option Explicit
Sub Main_Middle_three_digits()
Dim Numbers, i&
Numbers = Array(123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, _
100, -12345, 1, 2, -1, -10, 2002, -2002, 0)
For i = 0 To 16
Debug.Print Numbers(i) & " Return : " & Middle3digits(CStr(Numbers(i)))
Next
End Sub
Function Middle3digits(strNb As String) As String
If Left(strNb, 1) = "-" Then strNb = Right(strNb, Len(strNb) - 1)
If Len(strNb) < 3 Then
Middle3digits = "Error ! Number of digits must be >= 3"
ElseIf Len(strNb) Mod 2 = 0 Then
Middle3digits = "Error ! Number of digits must be odd"
Else
Middle3digits = Mid(strNb, 1 + (Len(strNb) - 3) / 2, 3)
End If
End Function
</syntaxhighlight>
{{out}}
<pre>123 Return : 123
12345 Return : 234
1234567 Return : 345
987654321 Return : 654
10001 Return : 000
-10001 Return : 000
-123 Return : 123
-100 Return : 100
100 Return : 100
-12345 Return : 234
1 Return : Error ! Number of digits must be >= 3
2 Return : Error ! Number of digits must be >= 3
-1 Return : Error ! Number of digits must be >= 3
-10 Return : Error ! Number of digits must be >= 3
2002 Return : Error ! Number of digits must be odd
-2002 Return : Error ! Number of digits must be odd
0 Return : Error ! Number of digits must be >= 3</pre>
=={{header|VBScript}}==
<syntaxhighlight lang="vb">'http://rosettacode.org/wiki/Middle_three_digits
Function mid3n(n)
'Remove the number's sign.
n = CStr(Abs(n))
If Len(n) < 3 Or Len(n) Mod 2 = 0 Then
mid3n = "Invalid: Either the length of n < 3 or an even number."
ElseIf Round(Len(n)/2) > Len(n)/2 Then
mid3n = Mid(n,Round(Len(n)/2)-1,3)
Else
mid3n = Mid(n,Round(Len(n)/2),3)
End If
End Function
'Calling the function.
arrn = Array(123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345,_
1,2,-1,-10,2002,-2002,0)
For Each n In arrn
WScript.StdOut.Write n & ": " & mid3n(n)
WScript.StdOut.WriteLine
Next</syntaxhighlight>
{{Out}}
<pre>
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
1: Invalid: Either the length of n < 3 or an even number.
2: Invalid: Either the length of n < 3 or an even number.
-1: Invalid: Either the length of n < 3 or an even number.
-10: Invalid: Either the length of n < 3 or an even number.
2002: Invalid: Either the length of n < 3 or an even number.
-2002: Invalid: Either the length of n < 3 or an even number.
0: Invalid: Either the length of n < 3 or an even number.
</pre>
=={{header|Vedit macro language}}==
<
#1 = Get_Num("Enter a number, or 0 to stop: ", STATLINE)
Ins_Text("Input: ") Num_Ins(#1, COUNT, 10)
Line 679 ⟶ 6,378:
}
Buf_Quit(OK)
Return </
Output:
Line 699 ⟶ 6,398:
Input: -2002 Result: Not odd number of digits!
Input: 0 Result: Too few digits! </pre>
=={{header|V (Vlang)}}==
<syntaxhighlight lang="v (vlang)">import math
const
(
valid = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345]
invalid = [1, 2, -1, -10, 2002, -2002, 0]
)
fn main() {
for elem in valid {println(middle(elem))}
for elem in invalid {println(middle(elem))}
}
fn middle(num int) string {
mut strip := math.abs(num).str()
if strip.len < 3 {return 'Error: $num has less than 3 digits'}
if strip.len % 2 == 0 {return 'Error: $num has an even number of digits'}
start := (strip.len / 2) - 1
return strip.substr(start, start + 3)
}
</syntaxhighlight>
{{out}}
<pre>
123
234
345
654
000
000
123
100
100
234
Error: 1 has less than 3 digits
Error: 2 has less than 3 digits
Error: -1 has less than 3 digits
Error: -10 has less than 3 digits
Error: 2002 has an even number of digits
Error: -2002 has an even number of digits
Error: 0 has less than 3 digits
</pre>
=={{header|Wart}}==
<syntaxhighlight lang="wart">def (mid3 n)
withs (digits (with outstring # itoa
(pr abs.n))
max len.digits
mid (int max/2))
if (and odd?.max (max >= 3))
(digits mid-1 mid+2)</syntaxhighlight>
'''Output'''
<pre>mid3.123
=> 123
mid3.12345
=> 234
mid3.1234567
=> 345
mid3.987654321
=> 654
mid3.10001
=> 000
mid3 -10001
=> 000
(mid3 -123)
=> 123
(mid3 -100)
=> 100
(mid3 100)
=> 100
(mid3 -12345)
=> 234
# Errors
mid3.1
=> nil
mid3.2
=> nil
mid3 -1
=> nil
mid3 -10
=> nil
mid3 2002
=> nil
mid3 -2002
=> nil
(mid3 0)
=> nil</pre>
=={{header|Wren}}==
{{libheader|Wren-fmt}}
<syntaxhighlight lang="wren">import "./fmt" for Fmt
var middle3 = Fn.new { |n|
if (n < 0) n = -n
var s = "%(n)"
var c = s.count
if (c < 3) return "Minimum is 3 digits, only has %(c)."
if (c%2 == 0) return "Number of digits must be odd, %(c) is even."
if (c == 3) return s
var d = (c - 3)/2
return s[d..d+2]
}
var a = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345,
1, 2, -1, -10, 2002, -2002, 0]
for (e in a) {
Fmt.print("$9d -> $n", e, middle3.call(e))
}</syntaxhighlight>
{{out}}
<pre>
123 -> 123
12345 -> 234
1234567 -> 345
987654321 -> 654
10001 -> 000
-10001 -> 000
-123 -> 123
-100 -> 100
100 -> 100
-12345 -> 234
1 -> Minimum is 3 digits, only has 1.
2 -> Minimum is 3 digits, only has 1.
-1 -> Minimum is 3 digits, only has 1.
-10 -> Minimum is 3 digits, only has 2.
2002 -> Number of digits must be odd, 4 is even.
-2002 -> Number of digits must be odd, 4 is even.
0 -> Minimum is 3 digits, only has 1.
</pre>
=={{header|XPL0}}==
<
func Mid3Digits(I); \Return the middle three digits of I
Line 724 ⟶ 6,559:
Text(0, Mid3Digits(Passing(X))); CrLf(0);
];
]</
{{out}}
Line 746 ⟶ 6,581:
Middle three digits of 0 returned: Must be 3, 5, 7 or 9 digits
</pre>
=={{header|zkl}}==
<syntaxhighlight lang="zkl">fcn middle(ns){
ns.apply("toString").apply('-("-"))
.apply(fcn(n){nl:=n.len();
if(nl<3 or nl.isEven) return(False);
n[(nl-3)/2,3] : "%03d".fmt(_)
})
}
middle(T(123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345)).println()
middle(T(1, 2, -1, -10, 2002, -2002, 0)).println();</syntaxhighlight>
{{out}}
<pre>
L("123","234","345","654","000","000","123","100","100","234")
L(False,False,False,False,False,False,False)
</pre>
Algorithm is convert each number into a string, remove any "-", reject strings less than 3 characters or are even in length, return middle three characters of remainder.
{{omit from|GUISS}}
| |||