Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!hsi!stpstn!lerman
From: lerman@stpstn.UUCP (Ken Lerman)
Newsgroups: comp.lang.c
Subject: Re: compiler detecting divide by zero
Message-ID: <5857@stpstn.UUCP>
Date: 27 Nov 90 15:21:42 GMT
References: <36233@cup.portal.com>
Reply-To: lerman@stpstn.UUCP (Ken Lerman)
Organization: The Stepstone Corporation, Sandy Hook, CT 06482
Lines: 58

In article <36233@cup.portal.com> ts@cup.portal.com (Tim W Smith) writes:
->For obscure reasons that I won't go into, I wanted a divide
->by zero in a program.  I was compiling on SCO Unix System V/386
->relase 2.2 (I think...) with whatever C compiler comes with
->this version of Unix.
->
->I tried the obvious:
->
->	int	i, j;
->
->	i = 1;
->	j = 0;
->	i/=j;
->
->The compiler caught this.  Grrr.  Next I tried:
->
->	i = 1;
->	j = 1;
->	i -= 1;
->	j/=i;
->
->It still caught it.  Double grrr!
->
->Next try:
->
->	int	i, j, *p;
->
->	i = 1;
->	j = 1;
->	p = &i;
->	j /= *p - 1;
->
->It still caught it!
->
->This one got past it:
->
->	j = 5;
->	for ( i = 0; i < 5; i++ )
->		j--;
->	i /= j;
->
->After the previous try, I was a bit surprised that it didn't
->figure out this one!
->
->						Tim Smith

I haven't tried it, but I'll bet that:

    int divide(int a, int b){ return a/b; }

will cause your divide error when called by:

    x = divide(1,0);

Of course, if your compiler is brilliant, you might have to put the
function divide in a separate file. :-)

Ken