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From: tlg@ukc.ac.uk (T.L.Goodwin)
Newsgroups: comp.lang.c
Subject: For vs while (was Re: Comparing strings...)
Message-ID: <2226@ukc>
Date: 17 Oct 90 11:14:44 GMT
References: <2205.271700c2@cc.nu.oz.au> <1990Oct13.190106.15615@ux1.cso.uiuc.edu> <10678.271ade27@amherst.bitnet> <1990Oct17.030157.460@ux1.cso.uiuc.edu>
Reply-To: tlg@ukc.ac.uk (T.L.Goodwin)
Organization: Computing Lab, University of Kent at Canterbury, UK.
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In article <1990Oct17.030157.460@ux1.cso.uiuc.edu> gordon@osiris.cso.uiuc.edu (John Gordon) writes:
>	Also, one other thing: for() and while() loops are essentially 
>identical.  The following loops are exactly the same:
>
>#1) 	    for(i = 0; i < 100; i++)
>	    {
>		body of loop
>	    }
>
>#2) 	   i = 0;
>	   while(i < 100)
>	   {
>	     body of loop
>	     i++;
>	   }

Almost, but not quite.  If the body of the loop contains a "continue",
then the second example becomes an infinite loop (other changes to i
and "break"s notwithstanding), since the increment is never reached.

John is not alone: this equivalence is wrongly claimed in Steve
Bourne's book "The UNIX System", and also K&R (2, I haven't got a copy
of 1 handy), although Bjarne Stroustrup gets it right in the C++
reference manual.

Regards,

Tim Goodwin.