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From: simonp@fulcrum.bt.co.uk (Simon Parsons)
Newsgroups: comp.lang.c
Subject: Re: Problem with post-incrementation
Message-ID: <1!{_*K$@uzi-9mm.fulcrum.bt.co.uk>
Date: 17 Apr 91 15:19:51 GMT
References: <6530@s3.ireq.hydro.qc.ca>
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Organization: BT Fulcrum, Birmingham
Lines: 34

In article <6530@s3.ireq.hydro.qc.ca> godin@ireq.hydro.qc.ca (Andre Godin 8926) writes:
>
>	Every times I call this function, the value of 'str' 
>	is always tmp_0 and 'i' never gets incremented. If
>	we use the pre-increment operator, the function works 
>	properly. Why post-incrementing doesn't work?
>
>	(I'm using cc under SunOs 4.0.3.)
>
>char *
>fnc() /*
>----- */
>{
>static	int	i = 0;
>static	char	str[256];
>
>	sprintf(str, "tmp_%d", i = (i++) % 3600);
>
>	return (str);
>}

No suprises there the expression on the right-hand side of the assignment
is evaluated to zero, i is post-incremented to 1. Then the value of the
expression ( 0 ) is assigned to i. Hence i remains at zero for each call
of the function.

Simon


--
        "Hey girl, as I've always said, I prefer your lips red, 
         Not what the good lord made, but what he intended."
                                                         
          Simon Parsons, BT Fulcrum - simonp@fulcrum.bt.co.uk