Detect division by zero: Difference between revisions
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Write a function to detect a ''divide by zero error'' without checking if the denominator is zero. |
Write a function to detect a ''divide by zero error'' without checking if the denominator is zero. |
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=={{header|68000 Assembly}}== |
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The <code>DIVU</code> and <code>DIVS</code> opcodes will automatically trigger a system call to Trap #5 if division by zero occurs. |
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=={{header|8th}}== |
=={{header|8th}}== |
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Revision as of 02:53, 8 September 2021
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
Write a function to detect a divide by zero error without checking if the denominator is zero.
68000 Assembly
The DIVU and DIVS opcodes will automatically trigger a system call to Trap #5 if division by zero occurs.
8th
Division by zero results in the value "Inf": <lang Forth> 1 0 n:/ Inf? . cr </lang>
- Output:
true
ABAP
<lang ABAP>report zdiv_zero data x type i. try.
x = 1 / 0.
catch CX_SY_ZERODIVIDE.
write 'Divide by zero.'.
endtry. </lang>
Ada
<lang ada>-- Divide By Zero Detection
with Ada.Text_Io; use Ada.Text_Io; with Ada.Float_Text_Io; use Ada.Float_Text_Io; with Ada.Integer_Text_Io; use Ada.Integer_Text_Io;
procedure Divide_By_Zero is
Fnum : Float := 1.0; Fdenom : Float := 0.0; Fresult : Float; Inum : Integer := 1; Idenom : Integer := 0; Iresult : Integer;
begin
begin
Put("Integer divide by zero: ");
Iresult := Inum / Idenom;
Put(Item => Iresult);
exception
when Constraint_Error =>
Put("Division by zero detected.");
end;
New_Line;
Put("Floating point divide by zero: ");
Fresult := Fnum / Fdenom;
if Fresult > Float'Last or Fresult < Float'First then
Put("Division by zero detected (infinite value).");
else
Put(Item => Fresult, Aft => 9, Exp => 0);
end if;
New_Line;
end Divide_By_Zero;</lang>
- Output:
Integer divide by zero: Division by zero detected. Floating point divide by zero: Division by zero detected (infinite value).
Aime
<lang aime>integer divide(integer n, integer d) {
return n / d;
}
integer can_divide(integer n, integer d) {
return !trap(divide, n, d);
}
integer main(void) {
if (!can_divide(9, 0)) {
o_text("Division by zero.\n");
}
return 0;
}</lang>
- Output:
Division by zero.
The Aime interpreter reports execution errors by default, printing on standard error:
aime: can_divide: 4: division by zero
ALGOL 68
The USSR's ALGOL 68 had a "GOST 27975-88 Programming language ALGOL 68 extended (Язык программирования АЛГОЛ 68 расширенный)" that included additional keywords on, exception, raise. This was an extension, and probably made only an appearance in the Leningrad compiler (Алгола 68 Ленинград).
The following code sample implements zero division, without using language extensions or access to hardware interrupts.
<lang algol68>PROC raise exception= ([]STRING args)VOID: (
put(stand error, ("Exception: ",args, newline));
stop
);
PROC raise zero division error := VOID:
raise exception("integer division or modulo by zero");
PROC int div = (INT a,b)REAL: a/b; PROC int over = (INT a,b)INT: a%b; PROC int mod = (INT a,b)INT: a%*b;
BEGIN
OP / = (INT a,b)REAL: ( b = 0 | raise zero division error; SKIP | int div (a,b) ); OP % = (INT a,b)INT: ( b = 0 | raise zero division error; SKIP | int over(a,b) ); OP %* = (INT a,b)INT: ( b = 0 | raise zero division error; SKIP | int mod (a,b) );
PROC a different handler = VOID: (
put(stand error,("caught division by zero",new line));
stop
);
INT x:=1, y:=0;
raise zero division error := a different handler;
print(x/y)
END</lang>
- Output:
caught division by zero
ALGOL W
Algol W allows the program to handle a number of system defined exceptions including INTDIVZERO and DIVZERO - integer and real division by zero.
A count of the number of times the exception is allowed is decremented each time the exception occurs. If this reaches 0, the program crashes. If it is greater than 0, the program continues and XCPNOTED(exception) returns true. This example uses this to detect integer and real division by 0. The INTDIVERO exception also occurs if the remainder (modulo) operator is used with 0.
<lang algolw>begin
% integer division procedure %
% sets c to a divided by b, returns true if the division was OK, %
% false if there was division by zero %
logical procedure divideI ( integer value a, b; integer result c ) ;
begin
% set exception handling to allow integer division by zero to occur once %
INTDIVZERO := EXCEPTION( false, 1, 0, false, "INTDIVZERO" );
c := a div b;
not XCPNOTED(INTDIVZERO)
end divideI ;
% real division procedure %
% sets c to a divided by b, returns true if the division was OK, %
% false if there was division by zero %
logical procedure divideR ( long real value a, b; long real result c ) ;
begin
% set exception handling to allow realdivision by zero to occur once %
DIVZERO := EXCEPTION( false, 1, 0, false, "DIVZERO" );
c := a / b;
not XCPNOTED(DIVZERO)
end divideR ;
integer c;
real d;
write( divideI( 4, 2, c ) ); % prints false as no exception %
write( divideI( 5, 0, c ) ); % prints true as division by zero was detected %
write( divideR( 4, 2, d ) ); % prints false as no exception %
write( divideR( 5, 0, d ) ) % prints true as division by zero was detected %
end.</lang>
Arturo
<lang rebol>try? -> 3/0 else -> print "division by zero" </lang>
- Output:
division by zero
AutoHotkey
<lang AutoHotkey>ZeroDiv(num1, num2) {
If ((num1/num2) != "") MsgBox % num1/num2 Else MsgBox, 48, Warning, The result is not valid (Divide By Zero).
} ZeroDiv(0, 3) ; is ok ZeroDiv(3, 0) ; divize by zero alert</lang>
BASIC
Applesoft BASIC
The error code for division by zero is 133. There is a good overview of Applesoft ONERR GOTO handling here: http://newsgroups.derkeiler.com/Archive/Comp/comp.sys.apple2.programmer/2010-04/msg00000.html
<lang BASIC> 100 REM TRY
110 ONERR GOTO 200 120 D = - 44 / 0 190 END 200 REM CATCH 210 E = PEEK (222) < > 133 220 POKE 216,0: REM ONERR OFF 230 IF E THEN RESUME 240 CALL - 3288: REM RECOVER 250 PRINT "DIVISION BY ZERO"
</lang>
BBC BASIC
<lang bbcbasic> PROCdivide(-44, 0)
PROCdivide(-44, 5)
PROCdivide(0, 5)
PROCdivide(5, 0)
END
DEF PROCdivide(numerator, denominator)
ON ERROR LOCAL IF FALSE THEN
REM 'Try' clause:
PRINT numerator / denominator
ELSE
REM 'Catch' clause:
CASE ERR OF
WHEN 18: PRINT "Division by zero"
WHEN 20: PRINT "Number too big"
OTHERWISE RESTORE LOCAL : ERROR ERR, REPORT$
ENDCASE
ENDIF
ENDPROC</lang>
IS-BASIC
<lang IS-BASIC>100 WHEN EXCEPTION USE ERROR 110 FOR I=5 TO-2 STEP-1 120 PRINT 10/I 130 NEXT 140 END WHEN 150 HANDLER ERROR 160 IF EXTYPE=3001 THEN PRINT EXSTRING$(EXTYPE);" in line";EXLINE 170 CONTINUE 180 END HANDLER</lang>
Liberty BASIC
<lang lb>result = DetectDividebyZero(1, 0)
Function DetectDividebyZero(a, b)
On Error GoTo [Error]
DetectDividebyZero= (a/ b)
Exit Function
[Error]
If Err = 11 Then '11 is the error number raised when divide by zero occurs
Notice "Divide by Zero Detected!"
End If
End Function</lang>
Locomotive Basic
<lang locobasic>10 ON ERROR GOTO 60 20 PRINT 2/3 30 PRINT 3/5 40 PRINT 4/0 50 END 60 IF ERR=11 THEN PRINT "Division by zero in line"ERL:RESUME 50</lang>
- Output:
0.666666667 0.6 Division by zero in line 40
PureBasic
PureBasic can be compiled with the OnError library included which gives a way to track program errors without losing speed, doing so gives support for the following functions;
- ErrorAddress()
- ErrorCode()
- ErrorFile()
- ErrorLine()
- ErrorMessage()
- ErrorRegister()
- ErrorTargetAddress()
- ExamineAssembly()
- InstructionAddress()
- InstructionString()
- NextInstruction()
- OnErrorCall()
- OnErrorDefault()
- OnErrorExit()
- OnErrorGoto()
- RaiseError()
This way the final version of a program can still intercept program errors and provide some function, or information about the error to the user so he can report it back to the developer.
With Integers & OnError Library
<lang PureBasic>;Set up a Procedure to handle any Error
Procedure MyErrorHandler()
Define txt$="The following error happened."+#CRLF$+ ErrorMessage()+"at line "+Str(ErrorLine())
MessageRequester("OnError test", txt$)
EndProcedure
- Tell where to go if an Error happens
OnErrorCall(@MyErrorHandler())
- Now, do something very stupid so that we may see an Error...
Repeat
A=Random(100)/Random(100)
ForEver</lang>
With Floats, and without OnError library
<lang PureBasic>Define.d a, b
Debug a/b</lang>
Results in;
-1.#IND
Run BASIC
<lang runbasic>on error goto [error] a = 1 / 0 wait
[error] ' error 11 is division by zero err number If err = 11 Then print "Division by Zero" wait</lang>
TI-89 BASIC
1/0 = undef is true.
Batch File
<lang dos>@echo off set /a dummy=5/0 2>nul
if %errorlevel%==1073750993 echo I caught a division by zero operation... exit /b 0</lang>
C
Technically, under the C standard, division by zero (regardless of type) is undefined behavior, so there is no standard way to run the division and then try to "detect" it later.
- The result of the / operator is the quotient from the division of the first operand by the second; the result of the % operator is the remainder. In both operations, if the value of the second operand is zero, the behavior is undefined.
- -- C99 standard, section 6.5.5 paragraph 5
Some systems will raise SIGFPE if a program divides by zero.
<lang c>#include <limits.h> /* INT_MIN */
- include <setjmp.h> /* siglongjmp(), sigsetjmp() */
- include <stdio.h> /* perror(), printf() */
- include <stdlib.h> /* exit() */
- include <signal.h> /* sigaction(), sigemptyset() */
static sigjmp_buf fpe_env;
/*
* This SIGFPE handler jumps to fpe_env. * * A SIGFPE handler must not return, because the program might retry * the division, which might cause an infinite loop. The only safe * options are to _exit() the program or to siglongjmp() out. */
static void fpe_handler(int signal, siginfo_t *w, void *a) { siglongjmp(fpe_env, w->si_code); /* NOTREACHED */ }
/*
* Try to do x / y, but catch attempts to divide by zero. */
void try_division(int x, int y) { struct sigaction act, old; int code; /* * The result must be volatile, else C compiler might delay * division until after sigaction() restores old handler. */ volatile int result;
/* * Save fpe_env so that fpe_handler() can jump back here. * sigsetjmp() returns zero. */ code = sigsetjmp(fpe_env, 1); if (code == 0) { /* Install fpe_handler() to trap SIGFPE. */ act.sa_sigaction = fpe_handler; sigemptyset(&act.sa_mask); act.sa_flags = SA_SIGINFO; if (sigaction(SIGFPE, &act, &old) < 0) { perror("sigaction"); exit(1); }
/* Do division. */ result = x / y;
/* * Restore old hander, so that SIGFPE cannot jump out * of a call to printf(), which might cause trouble. */ if (sigaction(SIGFPE, &old, NULL) < 0) { perror("sigaction"); exit(1); }
printf("%d / %d is %d\n", x, y, result); } else { /* * We caught SIGFPE. Our fpe_handler() jumped to our * sigsetjmp() and passes a nonzero code. * * But first, restore old handler. */ if (sigaction(SIGFPE, &old, NULL) < 0) { perror("sigaction"); exit(1); }
/* FPE_FLTDIV should never happen with integers. */ switch (code) { case FPE_INTDIV: /* integer division by zero */ case FPE_FLTDIV: /* float division by zero */ printf("%d / %d: caught division by zero!\n", x, y); break; default: printf("%d / %d: caught mysterious error!\n", x, y); break; } } }
/* Try some division. */ int main() { try_division(-44, 0); try_division(-44, 5); try_division(0, 5); try_division(0, 0); try_division(INT_MIN, -1); return 0; }</lang>
- Output:
using OpenBSD/amd64
-44 / 0: caught division by zero! -44 / 5 is -8 0 / 5 is 0 0 / 0: caught division by zero! -2147483648 / -1: caught division by zero!
The last line is a mistake: the system confused an overflow (INT_MIN / -1 would be INT_MAX + 1) with division by zero and raised SIGFPE. The system normally ignores overflow.
C#
The floating point types (float, double) don't raise an exception, but return the values Infinity or NaN as appropriate.
<lang csharp>using System;
namespace RosettaCode {
class Program {
static void Main(string[] args) {
int x = 1;
int y = 0;
try {
int z = x / y;
} catch (DivideByZeroException e) {
Console.WriteLine(e);
}
}
}
}</lang>
C++
<lang cpp>
- include<iostream>
- include<csignal> /* for signal */
- include<cstdlib>
using namespace std;
void fpe_handler(int signal) {
cerr << "Floating Point Exception: division by zero" << endl; exit(signal);
}
int main() {
// Register floating-point exception handler. signal(SIGFPE, fpe_handler);
int a = 1; int b = 0; cout << a/b << endl;
return 0;
} </lang>
Ceylon
<lang ceylon>shared void run() {
//integers divided by zero throw an exception try { value a = 1 / 0; } catch (Exception e) { e.printStackTrace(); }
//floats divided by zero produce infinity print(1.0 / 0 == infinity then "division by zero!" else "not division by zero!"); }</lang>
Clojure
After catching the ArithmeticException, print the error message, and then try and recover by returning some meaningful value. In this case, if x > 0, return +inf, if 0, NaN, otherwise -inf.
<lang lisp>(defn safe-/ [x y]
(try (/ x y)
(catch ArithmeticException _
(println "Division by zero caught!")
(cond (> x 0) Double/POSITIVE_INFINITY
(zero? x) Double/NaN
:else Double/NEGATIVE_INFINITY) )))</lang>
COBOL
<lang cobol>DIVIDE foo BY bar GIVING foobar
ON SIZE ERROR
DISPLAY "Division by zero detected!"
END-DIVIDE</lang>
Common Lisp
<lang lisp>(handler-case (/ x y)
(division-by-zero () (format t "division by zero caught!~%")))</lang>
D
<lang d>import std.stdio, std.string, std.math, std.traits;
string divCheck(T)(in T numer, in T denom) if (isIntegral!T || isFloatingPoint!T) {
Unqual!(typeof(numer / denom)) result; string msg;
static if (isIntegral!T) {
try {
result = numer / denom;
} catch(Error e) {
msg = "| " ~ e.msg ~ " (by Error)";
result = T.max;
}
} else { // Floating Point Type.
result = numer / denom;
if (numer.isNormal && result.isInfinity) {
msg = "| Division by Zero";
} else if (result != 0 && !result.isNormal) {
if (numer.isNaN)
msg = "| NaN numerator";
else if (denom.isNaN)
msg = "| NaN denominator";
else if (numer.isInfinity)
msg = "| Inf numerator";
else
msg = "| NaN (Zero Division by Zero)";
}
}
return format("%5s %s", format("%1.1g", real(result)), msg);
}
void main() {
writeln("Division with check:");
writefln("int 1/ 0: %s", divCheck(1, 0));
writefln("ubyte 1/ 0: %s", divCheck(ubyte(1), ubyte(0)));
writefln("real 1/ 0: %s", divCheck(1.0L, 0.0L));
writefln("real -1/ 0: %s", divCheck(-1.0L, 0.0L));
writefln("real 0/ 0: %s", divCheck(0.0L, 0.0L));
writeln;
writefln("real -4/-2: %s", divCheck(-4.0L,-2.0L));
writefln("real 2/-inf: %s", divCheck(2.0L, -real.infinity));
writeln;
writefln("real -inf/-2: %s", divCheck(-real.infinity, -2.0L));
writefln("real +inf/-2: %s", divCheck(real.infinity, -2.0L));
writefln("real nan/-2: %s", divCheck(real.nan, -2.0L));
writefln("real -2/ nan: %s", divCheck(-2.0L, real.nan));
writefln("real nan/ 0: %s", divCheck(real.nan, 0.0L));
writefln("real inf/ inf: %s",
divCheck(real.infinity, real.infinity));
writefln("real nan/ nan: %s", divCheck(real.nan, real.nan));
}</lang>
- Output:
Division with check: int 1/ 0: 2e+09 | Integer Divide by Zero (by Error) ubyte 1/ 0: 3e+02 | Integer Divide by Zero (by Error) real 1/ 0: inf | Division by Zero real -1/ 0: -inf | Division by Zero real 0/ 0: -nan | NaN (Zero Division by Zero) real -4/-2: 2 real 2/-inf: -0 real -inf/-2: inf | Inf numerator real +inf/-2: -inf | Inf numerator real nan/-2: nan | NaN numerator real -2/ nan: nan | NaN denominator real nan/ 0: nan | NaN numerator real inf/ inf: -nan | Inf numerator real nan/ nan: nan | NaN numerator
Delphi
<lang Delphi>program DivideByZero;
{$APPTYPE CONSOLE}
uses SysUtils;
var
a, b: Integer;
begin
a := 1;
b := 0;
try
WriteLn(a / b);
except
on e: EZeroDivide do
Writeln(e.Message);
end;
end.</lang>
Déjà Vu
<lang dejavu>divcheck x y:
true
try:
drop / x y
catch value-error:
not
if divcheck 1 0:
!print "Okay"
else:
!print "Division by zero"</lang>
- Output:
Division by zero
E
<lang e>def divide(numerator, denominator) {
def floatQuotient := numerator / denominator
if (floatQuotient.isNaN() || floatQuotient.isInfinite()) {
return ["zero denominator"]
} else {
return ["ok", floatQuotient]
}
}</lang>
ECL
Division by zero defaults to generating a zero result (0), rather than reporting a "divide by zero" error. This avoids invalid or unexpected data aborting a long job. The default behavior can be changed using #OPTION.
Evaluate to zero - default behavior <lang ECL> DBZ(REAL8 Dividend,INTEGER8 Divisor) := Quotient/Divisor;
- option ('divideByZero', 'zero');
DBZ(10,0); //returns 0.0 </lang> Stop and report a division by zero error: <lang ECL> DBZ(REAL8 Dividend,INTEGER8 Divisor) := Quotient/Divisor;
- option ('divideByZero', 'fail');
DBZ(10,0); //returns error message "Error: System error: -1: Division by zero (0, 0), -1," </lang> Returns "nan": <lang ECL> DBZ(REAL8 Dividend,INTEGER8 Divisor) := Quotient/Divisor;
- option ('divideByZero', 'nan');
DBZ(10,0); //returns 'nan'
/* NOTE: This is only currently supported for real numbers. Division by zero creates a quiet NaN,
which will propogate through any real expressions it is used in. You can use NOT ISVALID(x) to test if the value is a NaN. Integer and decimal division by zero continue to return 0.
- /
</lang>
Eiffel
version 2.4
In a file called main.e: <lang eiffel>class MAIN
creation main
feature main is
local
x, y: INTEGER;
retried: BOOLEAN;
do
x := 42;
y := 0;
if not retried then
io.put_real(x / y);
else
print("NaN%N");
end
rescue
print("Caught division by zero!%N");
retried := True;
retry
end
end</lang> Note: The "rescue" statement catches every exception.
Ela
<lang ela>open core number
x /. y = try Some (x `div` y) with
_ = None
(12 /. 2, 12 /. 0)</lang>
Output:
(Some 6, None)
Of course the cleanest way to implement the safe division function is through pattern matching:
<lang ela>x /. 0 = None x /. y = Some (x / y)</lang>
But it doesn't satisfy the task.
Elixir
<lang elixir>defmodule Division do
def by_zero?(x,y) do
try do
_ = x / y
false
rescue
ArithmeticError -> true
end
end
end
[{2, 3}, {3, 0}, {0, 5}, {0, 0}, {2.0, 3.0}, {3.0, 0.0}, {0.0, 5.0}, {0.0, 0.0}] |> Enum.each(fn {x,y} ->
IO.puts "#{x} / #{y}\tdivision by zero #{Division.by_zero?(x,y)}"
end)</lang>
- Output:
2 / 3 division by zero false 3 / 0 division by zero true 0 / 5 division by zero false 0 / 0 division by zero true 2.0 / 3.0 division by zero false 3.0 / 0.0 division by zero true 0.0 / 5.0 division by zero false 0.0 / 0.0 division by zero true
Emacs Lisp
Division by zero gives an error of type arith-error which can be caught in the usual ways with condition-case and similar. A division by zero example can be found in the Elisp manual section "Handling Errors".
<lang Lisp>(condition-case nil
(/ 1 0) (arith-error (message "Divide by zero (either integer or float)")))</lang>
Erlang
<lang erlang>div_check(X,Y) ->
case catch X/Y of
{'EXIT',_} -> true;
_ -> false
end.</lang>
ERRE
<lang ERRE> PROGRAM DIV_BY_ZERO
EXCEPTION
IF ERR=11 THEN PRINT("Division by Zero") END IF
END EXCEPTION
BEGIN
PRINT(0/3) PRINT(3/0)
END PROGRAM </lang> EXCEPTION (when it's present) detects runtime errors, otherwise program stops with a [Runtime error #nn] where nn is the error code. Error codes are different between C-64 and PC version.
- Output:
0 Division by zero
F#
<lang fsharp>let detectDivideZero (x : int) (y : int):int option =
try
Some(x / y)
with
| :? System.ArithmeticException -> None
printfn "12 divided by 3 is %A" (detectDivideZero 12 3)
printfn "1 divided by 0 is %A" (detectDivideZero 1 0)</lang>
Output:
12 divided by 3 is Some 4 1 divided by 0 is null
Factor
<lang factor>USE: math.floats.env
- try-div ( a b -- )
'[ { +fp-zero-divide+ } [ _ _ /f . ] with-fp-traps ] try ;</lang>
( scratchpad ) 1 2 try-div 0.5 ( scratchpad ) 1 0 try-div Floating point trap Type :help for debugging help.
Fancy
<lang fancy>def divide: x by: y {
try {
x / y
} catch DivisionByZeroError => e {
e message println # prints error message
}
} </lang>
Forth
<lang forth>: safe-/ ( x y -- x/y )
['] / catch -55 = if cr ." divide by zero!" 2drop 0 then ;</lang>
Fortran
Fortran has only floating-point exception handling. Integer exceptions are missing in ISO standard. Gfortran detects some integer explicit exceptions during compilation and is able to generate some run-time checks for integer overflow (with -ftrapv). Intel ifort does not have integer overflow / division by zero detection.
Floating-point division by zero detection.
<lang fortran> program rosetta_divbyzero
implicit none integer, parameter :: rdp = kind(1.d0) real(rdp) :: normal,zero
normal = 1.d0 zero = 0.d0
call div_by_zero_check(normal,zero)
contains
subroutine div_by_zero_check(x,y)
use, intrinsic :: ieee_exceptions
use, intrinsic :: ieee_arithmetic
implicit none
real(rdp), intent(in) :: x,y
real(rdp) :: check
type(ieee_status_type) :: status_value
logical :: flag
flag = .false.
! Get the flags
call ieee_get_status(status_value)
! Set the flags quiet
call ieee_set_flag(ieee_divide_by_zero,.false.)
write(*,*)"Inf supported? ",ieee_support_inf(check)
! Calculation involving exception handling
check = x/y
write(*,*)"Is check finite?",ieee_is_finite(check), check
call ieee_get_flag(ieee_divide_by_zero, flag)
if (flag) write(*,*)"Warning! Division by zero detected"
! Restore the flags
call ieee_set_status(status_value)
end subroutine div_by_zero_check
end program rosetta_divbyzero </lang>
Integer division by zero. No detection.
<lang fortran> program rosetta_integer_divbyzero
implicit none integer :: normal,zero,answer normal = 1 zero = 0 answer = normal/ zero write(*,*) answer
end program rosetta_integer_divbyzero </lang>
FreeBASIC
In FreeBASIC integer division by zero is a fatal error and cannot be caught by the language's built-in error handling constructs.
However, it is possible to detect such an error by using floating point division instead and relying on the fact that when Infinity, -Infinity and NaN are converted back to a 4 or 8 byte signed integer, the result is the lower bound of the range of the relevant integer type.
For Win64, an Integer is a signed 8 byte type and the returned value is therefore -9223372036854775808 which would be unlikely to arise in any other integer division scenario.
The following code relies on this 'hack':-
<lang freebasic>' FB 1.05.0 Win64
Const divByZeroResult As Integer = -9223372036854775808
Sub CheckForDivByZero(result As Integer)
If result = divByZeroResult Then Print "Division by Zero" Else Print "Division by Non-Zero" End If
End Sub
Dim As Integer x, y
x = 0 : y = 0 CheckForDivByZero(x/y) ' automatic conversion to type of parameter which is Integer x = 1 CheckForDivByZero(x/y) x = -1 CheckForDivByZero(x/y) y = 1 CheckForDivByZero(x/y) Print Print "Press any key to exit" Sleep</lang>
- Output:
Division by Zero Division by Zero Division by Zero Division by Non-Zero
FutureBasic
Stop on error. Error type reported in log console. <lang futurebasic> include "ConsoleWindow"
on error stop dim as long a print a / 0 </lang>
Gambas
Click this link to run this code <lang gambas>Public Sub Main()
Try Print 1 / 0 If Error Then Print Error.Text
End</lang> Output:
Division by zero
Go
Detection on integers by recovering from a panic: <lang go>package main
import "fmt"
func divCheck(x, y int) (q int, ok bool) {
defer func() {
recover()
}()
q = x / y
return q, true
}
func main() {
fmt.Println(divCheck(3, 2)) fmt.Println(divCheck(3, 0))
}</lang> Output:
1 true 0 false
Groovy
In Groovy, the float and double types follow IEEE numeric formats and rules. Here is a solution for double: <lang groovy>def dividesByZero = { double n, double d ->
assert ! n.infinite : 'Algorithm fails if the numerator is already infinite.' (n/d).infinite || (n/d).naN
}</lang>
Test program: <lang groovy>((3d)..(0d)).each { i ->
((2d)..(0d)).each { j ->
println "${i}/${j} divides by zero? " + dividesByZero(i,j)
}
}</lang>
Output:
3.0/2.0 divides by zero? false 3.0/1.0 divides by zero? false 3.0/0.0 divides by zero? true 2.0/2.0 divides by zero? false 2.0/1.0 divides by zero? false 2.0/0.0 divides by zero? true 1.0/2.0 divides by zero? false 1.0/1.0 divides by zero? false 1.0/0.0 divides by zero? true 0.0/2.0 divides by zero? false 0.0/1.0 divides by zero? false 0.0/0.0 divides by zero? true
Haskell
<lang haskell>import qualified Control.Exception as C check x y = C.catch (x `div` y `seq` return False)
(\_ -> return True)</lang>
hexiscript
<lang hexiscript>let a 1 let b 0 if tostr (a / (b + 0.)) = "inf"
println "Divide by Zero"
else
println a / b
endif</lang>
HicEst
<lang hicest>FUNCTION zero_divide(num, denom)
XEQ( num// "/" // denom, *99) ! on error jump to label 99 zero_divide = 0 ! division OK RETURN
99 zero_divide = 1
END</lang> <lang hicest>zero_divide(0, 1) returns 0 (false) zero_divide( 1, 3-2-1 ) returns 1 (true)</lang>
HolyC
HolyC throws Except:DivZero.
<lang holyc>try {
Print("%d\n", 10 / 0);
} catch {
Print("Divide by zero");
}</lang>
i
<lang i>//Division by zero is defined in 'i' so the result can be checked to determine division by zero. concept IsDivisionByZero(a, b) { c = a/b if c = 0 and a - 0 or a = 0 and c > 0 print( a, "/", b, " is a division by zero.") return end print( a, "/", b, " is not division by zero.") }
software { IsDivisionByZero(5, 0) IsDivisionByZero(5, 2) IsDivisionByZero(0, 0) }</lang>
Icon and Unicon
Setting &error to a non-zero number traps errors and converts then to failures. Division by zero generates error 201 <lang Icon>procedure main() &error := 1 udef := 1 / 0 | stop("Run-time error ", &errornumber, " : ", &errortext," in line #",&line," - converted to failure") end</lang>
Sample Output:
Run-time error 201 : division by zero in line #3 - converted to failure
IDL
<lang idl>if not finite( expression ) then ...</lang>
J
Generally, this task should be accomplished in J using 0=DEN. Here we take an approach that's more comparable with the other examples on this page.
Divide by zero is not an error in J. It results in infinity which is represented by an underscore ( _ ) or negative infinity (represented by a double underescore) or complex values which can have infinities for the real and/or imaginary part., except that 0 divided by 0 is defined to have the result zero (mathematically speaking any number is a valid result for 0 divided by 0, because 0 times any number is zero).
See also the J Dictionary page on infinity
So, anyways, the task:
<lang J>funnydiv=: 0 { [: (,:'division by zero detected')"_^:(_ e. |@,) (,>:)@:(,:^:(0<#@$))@[ %"_1 _ ]</lang>
This performs division and instead of returning the result returns the string 'division by zero detected' if a denominator was zero. Note that it also provides this result if a numerator was infinite, regardless of the denominator, but since there's no reasonable use for this implementation that's probably not a problem.
Examples:
<lang J> 3 funnydiv 2 1.5
3 funnydiv 0
division by zero detected
0 funnydiv 0
division by zero detected
0 funnydiv 3
0
2 3 4 funnydiv 5
0.4 0.6 0.8</lang>
Java
Two ways to accomplish this task are presented here. They each return true if there is a division by zero or if Double.POSITIVE_INFINITY is used as a numerator.
One way to do this check in Java is to use the isInfinite function from the Double class: <lang java>public static boolean infinity(double numer, double denom){ return Double.isInfinite(numer/denom); }</lang> Another way is to use the ArithmeticException as a check (which is not preferred because it expects an exception): <lang java>public static boolean except(double numer, double denom){ try{ int dummy = (int)numer / (int)denom;//ArithmeticException is only thrown from integer math return false; }catch(ArithmeticException e){return true;} }</lang>
JavaScript
JavaScript does not give an error on division by 0, and this is more useful than it is Mathematically correct. However, 0 divided by 0 will yield NaN, which is actually correct, since 0/0 is defined as "indeterminate". It may be better to return 0 or false in these situations, though, depending on the application (in JavaScript, 0 and false are the same thing): <lang JavaScript>function divByZero(dividend,divisor) { var quotient=dividend/divisor;
if(isNaN(quotient)) return 0; //Can be changed to whatever is desired by the programmer to be 0, false, or Infinity
return quotient; //Will return Infinity or -Infinity in cases of, for example, 5/0 or -7/0 respectively
} alert(divByZero(0,0));</lang> This will output "0" instead of "NaN". In this case, when checking against for true, the condition needs to be explicit ("===" rather than "==") because if divByZero(5,5) is used, this will return 1, which is the same as true when using "==".
jq
jq 1.4, like JavaScript, does not raise an error on division by 0, but unlike JavaScript, the result of division by zero is a number: either -1.7976931348623157e+308 or 1.7976931348623157e+308.
We can however define div(x;y) so that it raises an error, "NaN", if y equals 0: <lang jq>def div(x;y): if y==0 then error("NaN") else x/y end;</lang> In versions of jq since 1.4, we can then catch the error, as illustrated by the following snippet:<lang jq> try div(3;0) catch if "NaN" then "div by 0 error detected" else . end</lang>
Jsish
Like other ECMAScript implementations, Jsi does not error out on divide by zero. There is the internal representation of +Infinity, -Infinity and NaN. Detection of division by zero is not exact, other problems with the arithmetic can also set the state, but:
<lang javascript>if (!isFinite(numerator/denominator)) puts("result is infinity or not a number");</lang>
Julia
Julia handles division by zero quite gracefully. The result depends upon the numerator: Inf, -Inf, NaN or (for complex numbers) some mixture of these. This solution detects division by zero by checking for these sorts of values.
<lang julia>isdefinite(n::Number) = !isnan(n) && !isinf(n)
for n in (1, 1//1, 1.0, 1im, 0)
d = n / 0
println("Dividing $n by 0 ", isdefinite(d) ? "results in $d." : "yields an indefinite value ($d).")
end</lang>
- Output:
Divding 1 by 0 yields an indefinite value (Inf). Divding 1//1 by 0 yields an indefinite value (1//0). Divding 1.0 by 0 yields an indefinite value (Inf). Divding 0 + 1im by 0 yields an indefinite value (NaN + Inf*im). Divding 0 by 0 yields an indefinite value (NaN).
Kotlin
<lang scala>// version 1.1
fun divideByZero(x: Int, y:Int): Boolean =
try {
x / y
false
} catch(e: ArithmeticException) {
true
}
fun main(args: Array<String>) {
val x = 1
val y = 0
if (divideByZero(x, y)) {
println("Attempted to divide by zero")
} else {
@Suppress("DIVISION_BY_ZERO")
println("$x / $y = ${x / y}")
}
}</lang>
- Output:
Attempted to divide by zero
Lambdatalk
Thanks to Javascript a division by zero doesn't throw an error, just the word "Infinity". <lang scheme> {def DivByZero?
{lambda {:w}
{W.equal? :w Infinity}}}
{DivByZero? {/ 3 2}} -> false {DivByZero? {/ 3 0}} -> true </lang>
LabVIEW
This image is a VI Snippet, an executable image of LabVIEW code. The LabVIEW version is shown on the top-right hand corner. You can download it, then drag-and-drop it onto the LabVIEW block diagram from a file browser, and it will appear as runnable, editable code.
If the division node receives zero on both nodes (0/0), the Result will be "NaN"
Lasso
<lang Lasso>define dividehandler(a,b) => { ( #a->isNotA(::integer) && #a->isNotA(::decimal) || #b->isNotA(::integer) && #b->isNotA(::decimal) ) ? return 'Error: Please supply all params as integers or decimals' protect => { handle_error => { return 'Error: Divide by zero' } local(x = #a / #b) return #x } }
dividehandler(1,0)</lang>
- Output:
Error: Divide by zero
Lingo
<lang lingo>on div (a, b)
-- for simplicity type check of vars omitted
res = value("float(a)/b")
if voidP(res) then
_player.alert("Division by zero!")
else
return res
end if
end</lang>
Lua
Lua, like Javascript, does not error on DIVIDE-BY-ZERO, but returns infinity, -infinity or -nan. So:
<lang lua>local function div(a,b)
if b == 0 then error() end return a/b
end</lang>
M2000 Interpreter
To place a division as argument for lazy evaluation we have to use lazy$() which make a proper anonymous function. So we get a() as a function in DetectDivisionByZero() and try to execute. So if we get the specific error we get true.
Lazy$() not only make a function but also pass the same scope to that function where we use it. So Variables A, B, Z which they are in scope in module Checkit, and not in Function DetectDivisionByZero(), they used by the lazy evaluation contraction. References in M2000 passed as weak references, and for functions passed as code in a string (for objects passed the weak reference of the object plus the code). <lang M2000 Interpreter> Print function("{Read x : =x**2}", 2)=4 </lang>
For a fast way to check a valid expression we can use Valid() <lang M2000 Interpreter> Print Valid(100/0)=False </lang>
<lang M2000 Interpreter> Module Checkit {
Function DetectDivisionByZero(&a()) {
Try {
a=a()
}
=Error$=" division by zero"
}
Print DetectDivisionByZero(lazy$(10/0))=True
Z=10
A=4
B=0
Print DetectDivisionByZero(lazy$(Z/B))=True
Print DetectDivisionByZero(lazy$(Z/A))=False
} Checkit </lang>
M4
<lang M4>ifelse(eval(2/0),`',`detected divide by zero or some other error of some kind')</lang>
Output, with standard output labeled "==>" and error output labeled "error==>":
error==>divideby0.m4:1: m4: Divide by zero in eval: 2/0 ==>detected divide by zero or some other error of some kind
Maple
By default numeric exceptions raise errors which cannot be trapped by the usual try...catch mechanism. Instead numeric exceptions may be controlled by custom handling procedures.
<lang Maple>1/0; # Here is the default behavior.</lang>
Output:
Error, numeric exception: division by zero
Here is a simple custom handler being installed and used. <lang Maple>NumericEventHandler( ':-division_by_zero'
= proc() infinity; end proc ):
1/0;
NumericStatus(':-division_by_zero'); # We may check the status flag</lang> Output:
infinity
true
Alternatively, the custom handler could issue a warning or clear the status flag for that exception, as well as return some particular value. <lang Maple>NumericEventHandler( ':-division_by_zero'
= proc()
WARNING("division by zero");
NumericStatus(':-division_by_zero'=false):
infinity;
end proc ):
1/0;
NumericStatus(':-division_by_zero');</lang> Output:
Warning, division by zero
infinity
false
Mathematica / Wolfram Language
<lang Mathematica>Check[2/0, Print["division by 0"], Power::infy]</lang>
MATLAB
<lang Matlab>function [isDividedByZero] = dividebyzero(numerator, denomenator)
isDividedByZero = isinf( numerator/denomenator ); % If isDividedByZero equals 1, divide by zero occured.</lang>
Maxima
<lang maxima>f(a, b) := block([q: errcatch(a / b)], if emptyp(q) then 'error else q[1]);
f(5, 6); 5 / 6
f(5, 0;) 'error</lang>
MAXScript
<lang maxscript>if not bit.isFinite (expression) then...</lang>
min
The following operator will detect division by zero since the result will be infinity.
<lang min>(/ inf ==) :div-zero?</lang>
Integer divison (that is, div and not /) by zero will cause min to exit with an uncatchable arithmetic error.
mIRC Scripting Language
<lang mirc>var %n = $rand(0,1) if ($calc(1/ %n) == $calc((1/ %n)+1)) {
echo -ag Divides By Zero
} else {
echo -ag Does Not Divide By Zero
}</lang>
MUMPS
<lang MUMPS>DIV(A,B) ;Divide A by B, and watch for division by zero
;The ANSI error code for division by zero is "M9". ;$ECODE errors are surrounded by commas when set. NEW $ETRAP SET $ETRAP="GOTO DIVFIX^ROSETTA" SET D=(A/B) SET $ETRAP="" QUIT D
DIVFIX
IF $FIND($ECODE,",M9,")>1 WRITE !,"Error: Division by zero" SET $ECODE="" QUIT "" QUIT "" ; Fall through for other errors</lang>
Output:
USER>W $$DIV^ROSETTA(1,2) .5 USER>W $$DIV^ROSETTA(1,4) .25 USER>W $$DIV^ROSETTA(1,0) Error: Division by zero USER>W $$DIV^ROSETTA(1,C) W $$DIV^ROSETTA(1,C) ^ <UNDEFINED> *C
Nanoquery
<lang Nanoquery>def div_check(x, y) try (x / y) return false catch return true end end</lang>
Neko
Float, non-float as infinity and catching an $idiv. *Not demonstrated in a function.*
<lang ActionScript>/**
Detect division by zero
- /
var ans = 1.0 / 0.0 if $isinfinite(ans) $print("division by zero: ", ans, "\n")
ans = 1 / 0 if $isinfinite(ans) $print("division by zero: ", ans, "\n")
try $print($idiv(1, 0)) catch problem $print("idiv by zero: ", problem, "\n")</lang>
- Output:
prompt$ nekoc divide-zero.neko prompt$ neko divide-zero.n division by zero: inf division by zero: inf idiv by zero: $idiv
NetLogo
<lang netlogo>;; Division by zero detection using CAREFULLY
- The CAREFULLY clause exists in NetLogo since version 2.0
- In prior versions of NetLogo, you must examine the divisor prior to performing the division.
- The variables result, a, and b must all be previously created global, local, or agent -own'd variables.
- NetLogo variables are dynamically typed, so we are assuming that a and b contain numbers.
- (All numbers in NetLogo are double-precision floating-point numbers.)
- However, even if not numbers, the result is still the same
- the carefully clause will
- supress the run-time error and run the "commands if error" block, setting result to false.
- this false value can be detected, to alter the rest of the course of the code
- This behavior is consistent with other NetLogo primitives, such as POSTIION, that report
- FALSE, rather than a number, if the operation fails.
carefully [ ;; commands to try to run
set result a / b
] [ ;; commands to run if an error occurs in the previous block.
set result false
] ifelse is-number? result [ output-print (word a " / " b " = " result) ] [ output-print (word a " / " b " is not calculable" ]</lang>
NetRexx
<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols nobinary
method divide(dividend, divisor) public constant returns Rexx
do quotient = dividend / divisor catch exu = DivideException exu.printStackTrace() quotient = 'undefined' catch exr = RuntimeException exr.printStackTrace() quotient = 'error' end return quotient
method main(args = String[]) public static
-- process input arguments and set sensible defaults arg = Rexx(args) parse arg dividend .',' divisor . if dividend.length() = 0 then dividend = 1 if divisor.length() = 0 then divisor = 0 say dividend '/' divisor '=' divide(dividend, divisor) return
</lang> Output:
netrexx.lang.DivideException: Divide by 0 at netrexx.lang.Rexx.dodivide(Rexx.nrx:1778) at netrexx.lang.Rexx.OpDiv(Rexx.nrx:1674) at zz.divide(zz.nrx:20) at zz.main(zz.nrx:47)
NewLISP
<lang newlisp>#! /usr/local/bin/newlisp
(define (check-division x y)
(catch (/ x y) 'check-zero)
(if (not (integer? check-zero))
(setq check-zero "Division by zero."))
check-zero
)
(println (check-division 10 4)) (println (check-division 4 0)) (println (check-division 20 5)) (println (check-division 11 0))
(exit)</lang>
Output:
2 Division by zero. 4 Division by zero.
Nim
In version 1.4 and later, Nim makes a distinction between errors and defects. The first ones are exceptions which can be caught using an except clause. The second ones are non “catchable” exceptions which cause the program to abort. In version 1.4, by default, defects can still be caught, but this behavior is likely to change in next versions. Note that the distinction between errors and defects allow to process defects much more efficiently than errors.
Division by zero is now a defect and DivByZeroError is deprecated and replaced by DivByZeroDefect. So, the following program which catches a DivByZeroDefect is likely to fail to compile or execute correctly in future versions (but it is also very likely that using option --panics:off will restore the previous behavior).
In debug mode (the default), all checks are activated. In release mode (-d:release), checks are also activated. In danger mode (-d:danger) all checks are deactivated.
It is possible to declare the checks to activate or deactivate in some parts of code using a pragma, as in the following example.
<lang nim>{.push overflowChecks: on.} proc divCheck(x, y): bool =
try: discard x div y except DivByZeroDefect: return true return false
{.pop.} # Restore default check settings
echo divCheck(2, 0)</lang>
NS-HUBASIC
<lang NS-HUBASIC>10 ON ERROR GOTO 40 20 PRINT 1/0 30 END 40 IF ERR = 10 THEN PRINT "DIVISION BY ZERO IN LINE"ERL 50 RESUME 30</lang>
OCaml
Detection on integers by catching an exception: <lang ocaml>let div_check x y =
try ignore (x / y); false with Division_by_zero -> true</lang>
Detection on floats by checking for infiniteness: <lang ocaml>let div_check x y =
classify_float (x /. y) = FP_infinite</lang>
Octave
Dividing by zero raises a warning (a warning does not stop the execution), not an error (and the given answer is Infinity), so it's not possible to use a try-catch construct; we can however check for the lastwarn if the answer is Inf.
<lang octave>d = 5/0; if ( isinf(d) )
if ( index(lastwarn(), "division by zero") > 0 )
error("division by zero")
endif
endif</lang>
Oforth
<lang Oforth>: divideCheck(n) | e |
try: e [ 128 n / ] when: [ "Zero detected..." . ] "Leaving" println ;</lang>
Ol
Division by inexact zero produces Infinity (`+inf.0` and `-inf.0`) values, but division by exact zero (like `(/ n 0)`) - produces runtime error!
<lang scheme> (define (safediv a b)
(if (eq? (type b) type-complex)
(/ a b) ; complex can't be 0
(let ((z (/ 1 (inexact b))))
(unless (or (equal? z +inf.0) (equal? z -inf.0))
(/ a b)))))
- testing
(for-each (lambda (x)
(if x (print x) (print "division by zero detected")))
(list
(safediv 1 5) ; => 1/5
(safediv 2 0) ; => division by zero detected
(safediv 3 1+2i) ; => 3/5-6/5i
(safediv 4 0+i) ; => 0-4i
(safediv 5 7/5) ; => 25/7
)) </lang>
ooRexx
<lang ooRexx>/* REXX **************************************************************
- program demonstrates detects and handles division by zero.
- translated from REXX:
- removed fancy error reporting (ooRexx does not support linesize)
- removed label Novalue (as novalue is not enabled there)
- 28.04.2013 Walter Pachl
- /
Signal on Syntax /*handle all REXX syntax errors. */ x = sourceline() /*being cute, x=size of this pgm.*/ y = x-x /*setting to zero the obtuse way.*/ z = x/y /* attempt to divide by 0 */ exit /* will not be reached */
Syntax:
Say 'Syntax raised in line' sigl
Say sourceline(sigl)
Say 'rc='rc '('errortext(rc)')'
Exit 12</lang>
Output:
Syntax raised in line 11 z = x/y /* attempt to divide by 0 */ rc=42 (Arithmetic overflow/underflow)
Oz
For integer division only. <lang oz>try
{Show 42 div 0}
catch error(kernel(div0 ...) ...) then
{System.showInfo "Division by zero detected."}
end</lang>
PARI/GP
Pari/GP version 2.7 introduces iferr(). The given err variable is lexically bound in the recovery code and in the optional predicate (what to trap, default all errors). Error type e_INV is division by zero.
<lang parigp>iferr(1/0,
err,
print("division by 0"); print("or other non-invertible divisor"),
errname(err) == "e_INV");</lang>
Or the previous trap(),
<lang parigp>trap(,"division by 0",m/n)</lang>
Pascal
See Delphi
Perl
This function returns true iff its second argument is zero. <lang perl>sub div_check
{local $@;
eval {$_[0] / $_[1]};
$@ and $@ =~ /division by zero/;}</lang>
Phix
try integer i = 1/0 catch e ?e[E_USER] end try puts(1,"still running...\n")
- Output:
"attempt to divide by 0" still running...
PHP
This function returns true iff its second argument is zero. <lang php>function div_check($x, $y) {
@trigger_error(); // a dummy to detect when error didn't occur @($x / $y); $e = error_get_last(); return $e['message'] != ;
}</lang>
<lang php>function div_check($x, $y) {
return @($x / $y) === FALSE; // works at least in PHP/5.2.6-3ubuntu4.5
}</lang>
PicoLisp
<lang PicoLisp>(catch '("Div/0") (/ A B))</lang>
PL/I
<lang pli>Proc DivideDZ(a,b) Returns(Float Bin(33));
Dcl (a,b,c) Float Bin(33); On ZeroDivide GoTo MyError; c=a/b; Return(c);
MyError:
Put Skip List('Divide by Zero Detected!');
End DivideDZ;
xx=DivideDZ(1,0);</lang>
PL/SQL
<lang PLSQL>FUNCTION divide(n1 IN NUMBER, n2 IN NUMBER) RETURN BOOLEAN IS
result NUMBER;
BEGIN
result := n1/n2; RETURN(FALSE);
EXCEPTION
WHEN ZERO_DIVIDE THEN RETURN(true);
end divide;</lang>
<lang PL/SQL>divide(0,1) --false divide(1,0) --true, division by zero</lang>
PowerShell
<lang PowerShell> function div ($a, $b) {
try{$a/$b}
catch{"Bad parameters: `$a = $a and `$b = $b"}
} div 10 2 div 1 0 </lang>
- Output:
5 Bad parameters: $a = 1 and $b = 0
Prolog
<lang prolog> div(A, B, C, Ex) :-
catch((C is A/B), Ex, (C = infinity)).
</lang>
- Output:
?- div(10, 5, X, Ex). X = 2. ?- div(1, 0, X, Ex). X = infinity, Ex = error(evaluation_error(zero_divisor), context((/)/2, _2950)).
Pure
Floating point division yields inf or nan values as appropriate (if the FPU supports IEEE 754):
<lang pure>> 1/0, -1/0, 0/0; inf,-inf,nan</lang>
It's possible to check for these values as follows:
<lang pure>> inf_or_nan x = infp x || nanp x; > map inf_or_nan [1/0, -1/0, 0/0]; [1,1,1]</lang>
In contrast, integer division by zero raises an exception which can be caught as follows:
<lang pure>> divide n m = catch (\_ -> "divide by 0") (n div m); > divide 0 1; 0 > divide 1 0; "divide by 0"</lang>
Python
<lang python>def div_check(x, y):
try: x / y except ZeroDivisionError: return True else: return False</lang>
Q
Division by zero does not raise an error, instead it results in an infinity (0w or -0w) or NaN (0n).
<lang q>r:x%0 ?[1=sum r=(0n;0w;-0w);"division by zero detected";()]</lang>
R
Division by zero does not raise an error nor a warning. Division of a non-zero value by zero returns infinity. Division of zero by zero returns NaN; Whether the result is not finite can be checked: <lang rsplus>d <- 5/0 if ( !is.finite(d) ) {
# it is Inf, -Inf, or NaN
}</lang>
Racket
In Racket, the division by zero exception can be caught directly:
<lang racket>
- lang racket
(with-handlers ([exn:fail:contract:divide-by-zero?
(λ (e) (displayln "Divided by zero"))]) (/ 1 0))
</lang>
Raku
(formerly Perl 6)
Try/Catch
<lang perl6>sub div($a, $b) {
my $r;
try {
$r = $a / $b;
CATCH {
default { note "Unexpected exception, $_" }
}
}
return $r // Nil;
} say div(10,2); say div(1, sin(0));</lang>
- Output:
5 Unexpected exception, Attempt to divide 1 by zero using / Nil
Multi Method Dispatch
<lang perl6>multi div($a, $b) { return $a / $b } multi div($a, $b where { $b == 0 }) { note 'Attempt to divide by zero.'; return Nil }
say div(10, 2); say div(1, sin(0));</lang>
- Output:
5 Attempt to divide by zero. Nil
REBOL
<lang REBOL>REBOL [
Title: "Detect Divide by Zero" URL: http://rosettacode.org/wiki/Divide_by_Zero_Detection
]
- The 'try' word returns an error object if the operation fails for
- whatever reason. The 'error?' word detects an error object and
- 'disarm' keeps it from triggering so I can analyze it to print the
- appropriate message. Otherwise, any reference to the error object
- will stop the program.
div-check: func [ "Attempt to divide two numbers, report result or errors as needed." x y /local result ] [ either error? result: try [x / y][ result: disarm result print ["Caught" result/type "error:" result/id] ] [ print [x "/" y "=" result] ] ]
div-check 12 2 ; An ordinary calculation. div-check 6 0 ; This will detect divide by zero. div-check "7" 0.0001 ; Other errors can be caught as well.</lang>
Output:
12 / 2 = 6 Caught math error: zero-divide Caught script error: cannot-use
REXX
The task's requirements are to write a function, but this example program was written to solve the spirit of the requirement.
This version isn't really a function so much as it is a method.
Also, a function and a subroutine doesn't have that much of a distinction in the REXX language.
<lang rexx>/*REXX program demonstrates detection and handling division by zero. */
signal on syntax /*handle all REXX syntax errors. */
x = sourceline() /*being cute, x=is the size of this pgm*/
y = x - x /*setting to zero the obtuse way. */
z = x / y /*this'll trigger it, furrrr shurrre. */
exit /*We're kaput. Ja vohl ! */
/*──────────────────────────────────────────────────────────────────────────────────────*/
err: if rc==42 then do; say /*first, check for a specific error. */
say center(' ***error*** ', 79, "═")
say 'Division by zero detected at line ' @ ,
" and the REXX statement is:"
say sourceLine(@)
say
exit 42
end
say
say center(' error! ', 79, "*")
do #=1 for arg(); say; say arg(#); say
end /*#*/
exit 13
/*──────────────────────────────────────────────────────────────────────────────────────*/ syntax: @=sigl; call err 'REXX program' condition("C") 'error', condition('D'), ,
'REXX source statement (line' sigl"):", sourceLine(sigl)</lang>
- output:
═════════════════════════════════ ***error*** ═════════════════════════════════ Division by zero detected at line 5 and the REXX statement is: z = x / y /*this'll trigger it, furrrr shurrre. */
Ring
<lang ring> Try
see 9/0
Catch
see "Catch!" + nl + cCatchError
Done </lang>
RPGIV
<lang rpgiv>
dcl-c DIVIDE_BY_ZERO 00102;
dcl-s result zoned(5:2);
dcl-s value1 zoned(5:2);
dcl-s value2 zoned(5:2);
value1 = 10;
value2 = 0;
monitor;
eval(h) result = value1 / value2; // Using half rounding here for the eval result
on-error DIVIDE_BY_ZERO;
// Initialise the result to 0. Consider other messaging perhaps.
result = 0;
endmon;
*inlr = *on;
</lang>
Ruby
This only checks integer division by zero.
<lang ruby>def div_check(x, y)
begin x / y rescue ZeroDivisionError true else false end
end</lang>
Ruby allows division by zero if either operand is a Float.
<lang ruby>irb(main):010:0> div_check(5, 0) => true irb(main):011:0> div_check(5.0, 0) => false</lang>
Starting with Ruby 1.9, Numeric#div raises ZeroDivisionError, whether or not an operand is a Float.
<lang ruby>def div_check(x, y)
begin x.div y rescue ZeroDivisionError true else false end
end</lang>
<lang ruby>irb(main):010:0> div_check(5, 0) => true irb(main):011:0> div_check(5.0, 0) => true</lang>
Rust
<lang rust>fn test_division(numerator: u32, denominator: u32) {
match numerator.checked_div(denominator) {
Some(result) => println!("{} / {} = {}", numerator, denominator, result),
None => println!("{} / {} results in a division by zero", numerator, denominator)
}
}
fn main() {
test_division(5, 4); test_division(4, 0);
}</lang>
Scala
Without the "println(result)" line, the result would not get calculated as it is not needed. The method would get optimized to always return false. <lang scala>object DivideByZero extends Application {
def check(x: Int, y: Int): Boolean = {
try {
val result = x / y
println(result)
return false
} catch {
case x: ArithmeticException => {
return true
}
}
}
println("divided by zero = " + check(1, 0))
def check1(x: Int, y: Int): Boolean = {
import scala.util.Try
Try(y/x).isFailure
}
println("divided by zero = " + check1(1, 0))
}</lang>
Seed7
Integer division by zero raises NUMERIC_ERROR. Floating point division by zero returns Infinity or -Infinity. <lang seed7>$ include "seed7_05.s7i";
include "float.s7i";
const proc: doDivide (in integer: numer, in integer: denom) is func
begin
block
writeln(numer <& " div " <& denom <& " = " <& numer div denom);
exception
catch NUMERIC_ERROR:
writeln("Division by zero detected.");
end block;
end func;
const proc: doDivide (in float: numer, in float: denom) is func
local
var float: quotient is 0.0;
begin
quotient := numer / denom;
if quotient <> Infinity and quotient <> -Infinity then
writeln(numer <& " / " <& denom <& " = " <& quotient);
else
writeln("Division by zero detected.");
end if;
end func;
const proc: main is func
begin doDivide(10, 8); doDivide(1, 0); doDivide(10.0, 8.0); doDivide(1.0, 0.0); end func;</lang>
Output:
10 div 8 = 1 Division by zero detected. 10.0 / 8.0 = 1.25 Division by zero detected.
Sidef
The numerical system of Sidef evaluates `x/0` to `+/-Inf`. <lang ruby>func div_check(a, b){
var result = a/b result.abs == Inf ? nil : result
} say div_check(10, 2) # 5 say div_check(1, 0) # nil (detected)</lang>
Alternatively, we can do:
<lang ruby>func div_check(a, b){
Perl.eval("#{a} / #{b}")
} say div_check(10, 2) # 5 say div_check(1, 0) # nil (detected)</lang>
Slate
<lang slate>[ 1 / 0 ] on: Error do: [|:err| err return: PositiveInfinity].</lang>
Smalltalk
The behavior is the same for all number types (Integer, Float, Fraction, etc.). ZeroDivision raises an exception which can be caught to abort or proceed with a repair-value.
<lang smalltalk>|didDivideByZero a b|
didDivideByZero := false. a := 10. b := 0. [
a/b
] on: ZeroDivide do:[:ex |
'you tried to divide %P by zero\n' printf:{ex suspendedContext receiver} on:Transcript.
didDivideByZero := true.
]. didDivideByZero ifTrue:[
Transcript show:'bad bad bad, but I already told you in the handler'.
].</lang> Note: works in all Smalltalks: printf is available in the public domain printfScanf package (or already included in your dialect).
Alternative version, which gets any block as argument, evaluates it and returns true, if ZeroDivide happened (works in all Smalltalks):
<lang smalltalk>testZeroDivide :=
[:aBlock |
[
aBlock value.
false
] on: ZeroDivide do: [true].
].
"Testing" testZeroDivide value: [2/1] "------> false" testZeroDivide value: [2/0] "------> true"</lang>
of course, as ZeroDivide inherits from Error, you could also write <lang smalltalk>[...] on:Error do: [...]</lang>thereby catching ANY error (as done in some other code examples here).
You can also provide an alternative value from the exception handler:
<lang smalltalk>|a b result| a := 10. b := 0. result := [a / b] on:ZeroDivide do:[:ex | ex proceedWith:Float infinity]. Transcript showCR:result.</lang> will show "inf" on the console window.
SNOBOL4
Using setexit( ) to trap and ignore division by zero.
<lang SNOBOL4> define('zdiv(x,y)') :(zdiv_end) zdiv &errlimit = 1; setexit(.ztrap)
zdiv = x / y :(return)
ztrap zdiv = ?(&errtype ? (14 | 262)) 'Division by zero' :s(continue)f(abort) zdiv_end
- # Test and display
output = '1/1 = ' zdiv(1,1) ;* Integers non-zero
output = '1.0/1.0 = ' zdiv(1.0,1.0) ;* Reals non-zero
output = '1/0 = ' zdiv(1,0) ;* Integers zero
output = '1.0/0.0 = ' zdiv(1.0,0.0) ;* Reals zero
output = 'Zero checks complete'
end</lang>
Output:
1/1 = 1 1.0/1.0 = 1. 1/0 = Division by zero 1.0/0.0 = Division by zero Zero checks complete
SQL PL
version 9.7 or higher.
With SQL PL: <lang sql pl> --#SET TERMINATOR @
SET SERVEROUTPUT ON@
CREATE OR REPLACE FUNCTION DIVISION(
IN NUMERATOR DECIMAL(5, 3), IN DENOMINATOR DECIMAL(5, 3) ) RETURNS SMALLINT BEGIN DECLARE RET SMALLINT DEFAULT 1; DECLARE TMP DECIMAL(5, 3); DECLARE CONTINUE HANDLER FOR SQLSTATE '22012' SET RET = 1;
SET RET = 0; SET TMP = NUMERATOR / DENOMINATOR; RETURN RET; END @
VALUES DIVISION(10, 2)@ VALUES DIVISION(10, 3)@ VALUES DIVISION(10, 0)@ </lang> Output:
db2 -td@
db2 => CREATE OR REPLACE FUNCTION DIVISION(
...
db2 (cont.) => END @
DB20000I The SQL command completed successfully.
VALUES DIVISION(10, 2)
1
------
0
1 record(s) selected.
VALUES DIVISION(10, 3)
1
------
0
1 record(s) selected.
VALUES DIVISION(10, 0)
1
------
1
1 record(s) selected.
Standard ML
Detection on integers by catching an exception: <lang sml>fun div_check (x, y) = (
ignore (x div y); false
) handle Div => true</lang>
Detection on floats by checking for infiniteness: <lang sml>fun div_check (x, y) =
not (Real.isFinite (x / y))</lang>
Stata
In stata, a division by zero is silently replaced with a missing value. It would be possible to check whether the result is a missing value, but there may be another cause: one of the arguments is a missing value, or there is an overflow (for instance 1e200/1e-200). Therefore, it's not possible to detect precisely a division by zero, without checking the denominator.
Tcl
<lang tcl>proc div_check {x y} {
if {[catch {expr {$x/$y}} result] == 0} {
puts "valid division: $x/$y=$result"
} else {
if {$result eq "divide by zero"} {
puts "caught division by zero: $x/$y -> $result"
} else {
puts "caught another error: $x/$y -> $result"
}
}
}
foreach denom {1 0 foo} {
div_check 42 $denom
}</lang>
- Output:
valid division: 42/1=42 caught division by zero: 42/0 -> divide by zero caught another error: 42/foo -> can't use non-numeric string as operand of "/"
It is easier to trap such errors in Tcl 8.6, which has an additional control structure for exception processing: <lang tcl>proc div_check {x y} {
try {
puts "valid division: $x/$y=[expr {$x/$y}]"
} trap {ARITH DIVZERO} msg {
puts "caught division by zero: $x/$y -> $msg"
} trap {ARITH DOMAIN} msg {
puts "caught bad division: $x/$y -> $msg"
} on error msg {
puts "caught another error: $x/$y -> $msg"
}
}
foreach {num denom} {42 1 42 0 42.0 0.0 0 0 0.0 0.0 0 foo} {
div_check $num $denom
}</lang>
which produces the
- Output:
valid division: 42/1=42 caught division by zero: 42/0 -> divide by zero valid division: 42.0/0.0=Inf caught division by zero: 0/0 -> divide by zero caught bad division: 0.0/0.0 -> domain error: argument not in valid range caught another error: 0/foo -> can't use non-numeric string as operand of "/"
As can be seen, division-by-zero is only signaled when performing integer division. Similarly, separate detection of values that would otherwise be IEEE NaN is only performed when doing floating-point division.
TXR
<lang txr>@(do (defun div-check (x y)
(catch (/ x y)
(numeric_error (msg)
'div-check-failed))))
@(bind good @(div-check 32 8)) @(bind bad @(div-check 42 0))</lang>
Run:
$ txr -B division-by-zero.txr good="4.0" bad="div-check-failed"
Ursa
<lang ursa>def div_check (int x, int y) try / x y return false catch divzeroerror return true end try end</lang>
VAX Assembly
<lang VAX Assembly>65 64 69 76 69 64 00000008'010E0000' 0000 1 desc: .ascid "divide by zero"
6F 72 65 7A 20 79 62 20 000E
0000 0016 2 .entry handler,0
E5 AF 7F 0018 3 pushaq desc
00000000'GF 01 FB 001B 4 calls #1, g^lib$put_output
04 0022 5 ret
0023 6
0000 0023 7 .entry main,0
6D EE AF 9E 0025 8 movab handler, (fp) ;register exception handler
50 01 00 C7 0029 9 divl3 #0, #1, r0
04 002D 10 ret
002E 11
002E 12 .end main
$ run dv divide by zero </lang>
VBA
<lang vb> Option Explicit
Sub Main() Dim Div
If CatchDivideByZero(152, 0, Div) Then Debug.Print Div Else Debug.Print "Error" If CatchDivideByZero(152, 10, Div) Then Debug.Print Div Else Debug.Print "Error"
End Sub
Function CatchDivideByZero(Num, Den, Div) As Boolean
On Error Resume Next Div = Num / Den If Err = 0 Then CatchDivideByZero = True On Error GoTo 0
End Function</lang>
- Output:
Error 15,2
VBScript
<lang vb> Function div(num,den) On Error Resume Next n = num/den If Err.Number <> 0 Then div = Err.Description & " is not allowed." Else div = n End If End Function
WScript.StdOut.WriteLine div(6,3) WScript.StdOut.WriteLine div(6,0) WScript.StdOut.WriteLine div(7,-4) </lang>
- Output:
2 Division by zero is not allowed. -1.75
Visual Basic .NET
<lang vbnet>Module DivByZeroDetection
Sub Main()
Console.WriteLine(safeDivision(10, 0))
End Sub
Private Function safeDivision(v1 As Integer, v2 As Integer) As Boolean
Try
Dim answer = v1 / v2
Return False
Catch ex As Exception
Return True
End Try
End Function
End Module </lang>
- Output:
True
Wren
<lang ecmascript>var checkDivByZero = Fn.new { |a, b|
var c = a / b if (c.isInfinity || c.isNan) return true return false
}
System.print("Division by zero?") System.print(" 0 / 0 -> %(checkDivByZero.call(0, 0))") System.print(" 1 / 0 -> %(checkDivByZero.call(1, 0))") System.print(" 1 / 1 -> %(checkDivByZero.call(1, 1))")</lang>
- Output:
Division by zero? 0 / 0 -> true 1 / 0 -> true 1 / 1 -> false
XPL0
GetErr is an intrinsic function that detects runtime errors, such as division by zero, as well as more than a dozen others. Normally runtime errors terminate a program and display an error message. However the Trap intrinsic is used here to prevent error termination, which enables the program to do its own error handling. This example displays "Divide by zero".
<lang XPL0>include c:\cxpl\codes; int A, B; [Trap(false); \turn off error trapping B:= 1234/(A-A); \(error not detected at compile time) if GetErr then Text(0, "Divide by zero"); ]</lang>
Yorick
<lang yorick>func div_check(x, y) {
if(catch(0x01))
return 1;
temp = x/y;
return 0;
}</lang>
zkl
<lang zkl>fcn f(x,y){try{x/y}catch(MathError){println(__exception)}}</lang>
- Output:
zkl: f(1,0) MathError(INF (number is infinite), Int divide by zero) zkl: f(1.0,0) MathError(INF (number is infinite))
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