Loops/While
You are encouraged to solve this task according to the task description, using any language you may know.
Start an integer value at 1024. Loop while it is greater than 0. Print the value (with a newline) and divide it by two each time through the loop.
ActionScript
<actionscript> var i:int = 1024; while (i > 0) {
trace(i); i /= 2;
} </actionscript>
Ada
<ada> declare
I : Integer := 1024;
begin
while I > 0 loop
Put_Line(Integer'Image(I));
I := I / 2;
end loop;
end; </ada>
BASIC
<qbasic>i = 1024 while i > 0
print i i = i / 2
wend</qbasic>
Befunge
84*:*> :v
^/2.:_@
C
<c>int i = 1024; while(i > 0) {
printf("%d\n", i);
i /= 2;
}</c>
C#
<c>int i = 1024; while(i > 0){
System.Console.WriteLine(i); i /= 2;
}</c>
ColdFusion
Remove the leading space from the line break tag.
With tags:
<cfset i = 1024 /> <cfloop condition="i GT 0"> #i#< br /> <cfset i /= 2 /> </cfloop>
With script:
<cfscript>
i = 1024;
while( i > 0 )
{
writeOutput( i + "< br/ >" );
}
</cfscript>
Common Lisp
<lisp>(setq i 1024) (loop while (> i 0) do
(print i) (setq i (floor i 2)))</lisp>
D
<D>import std.stdio;
int i = 1024; void main() {
while(i > 0) {
writefln("%s", i);
i >>= 1;
}
}</d>
Forth
: halving ( n -- ) begin dup 0 > while cr dup . 2/ repeat drop ; 1024 halving
Factor
1024 [ dup 0 > ] [ dup . 2 /i ] [ drop ] while
Fortran
INTEGER :: i = 1024 DO WHILE (i > 0) WRITE(*,*) i i = i / 2 END DO
Haskell
import Control.Monad
main = loop 1024
where loop n = when (n > 0)
(do print n
loop (n `div` 2))
Icon
procedure main() local i i := 1024 while write(0 < (i := i / 2)) end
J
J is array-oriented, so there is very little need for loops. For example, one could satisfy this task this way:
,. <.@-:^:*^:a: 1024
J does support loops for those times they can't be avoided (just like many languages support gotos for those time they can't be avoided).
3 : 0 ] 1024
while. 0 < y do.
y 1!:2 ] 2
y =. <. -: y
end.
i. 0 0
)
Though it's rare to see J code like this.
Java
<java>int i = 1024; while(i > 0){
System.out.println(i); i >>= 1; //also acceptable: i /= 2;
}</java>
JavaScript
<javascript>var n = 1024; while (n>0) {
print(n); n/=2;
}</javascript>
Logo
make "n 1024 while [:n > 0] [print :n make "n :n / 2]
MAXScript
a = 1024
while a > 0 do
(
print a
a /= 2
)
Make
NEXT=`expr $* / 2`
MAX=10
all: $(MAX)-n;
0-n:;
%-n: %-echo
@-make -f while.mk $(NEXT)-n MAX=$(MAX)
%-echo:
@echo $*
Invoking it
|make -f while.mk MAX=1024
Oberon-2
PROCEDURE DivBy2*();
VAR i: INTEGER;
BEGIN
i := 1024;
WHILE i > 0 DO
Out.Int(i,0);
Out.Ln;
i := i DIV 2;
END;
END DivBy2;
OCaml
<ocaml>let n = ref 1024;; while !n > 0 do
Printf.printf "%d\n" !n; n := !n / 2
done;;</ocaml>
But it is more common to write it in a tail-recursive functional style: <ocaml>let rec loop n =
if n > 0 then begin Printf.printf "%d\n" n; loop (n / 2) end
in loop 1024</ocaml>
Pascal
<pascal> program divby2(output);
var
i: integer;
begin
i := 1024;
while i > 0 do
begin
writeln(i);
i := i div 2
end
end. </pascal>
Perl
<perl>$n = 1024; while ($n > 0) {
print "$n\n"; $n >>= 1; # also acceptable: use integer; $n /= 2;
}</perl>
PHP
<php>$i = 1024; while ($i > 0) {
echo "$i\n"; $i >>= 1;
}</php>
Pop11
lvars i = 1024;
while i > 0 do
printf(i, '%p\n');
i div 2 -> i;
endwhile;
Python
<python>n = 1024 while n > 0:
print n n //= 2</python>
Ruby
i = 1024 while i > 0 do
puts i i /= 2
end
Scheme
<scheme> (do ((n 1024 (quotient n 2)))
((<= n 0)) (display n) (newline))</scheme>
UnixPipes
(echo 1024>p.res;tail -f p.res) | while read a ; do test $a -gt 0 && (expr $a / 2 >> p.res ; echo $a) || exit 0 done
V
1024 [0 >] [ dup puts 2 / >int ] while
Visual Basic .NET
Dim x = 1024
Do
Console.WriteLine(x)
x = x \ 2
Loop While x > 0