From: wajnberg AT antibes DOT inra DOT fr (Eric Wajnberg)
Newsgroups: comp.os.msdos.djgpp
Subject: Strange behavior in loops!!
Date: 22 Mar 2001 13:13:44 GMT
Organization: I.N.R.A. Antibes (France) - Ecologie des Parasitoides
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I just got the strange following behavior with DJGPP that looks
like an error to me.

The following simple code:

#include <stdio.h>
int main(void)
{
 float from=3,to=5,by=.5;
 float x;
 for (x=from;x<=to;x+=by)
   (void)printf("%g\n",x);
 return 0;
}

produces of course the values 3, 3.5, 4, 4.5 and 5.

Up to now things are ok.

Now look at the following other code:

#include <stdio.h>
int main(void)
{
 float from=.3,to=.5,by=.05;
 float x;
 for (x=from;x<=to;x+=by)
  (void)printf("%g\n",x);
 return 0;
}

Which is exactly the same than the previous one except that all values
have been divided by 10.

In that case, the values outputted are .3, .35, .4, and .45.

In other words the value ".5" (i.e., the last one) is not outputted.

Strange, isn'it?

Of course the real problem I am facing now is much more complicated than
this one (the length of my code is currently of several thousand lines), but
these small examples explain it clearly.

I've made several other tests, but I'm keeping on obtaining the same problem.

Did I missed something?

Thanks for any help on that.


    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~   
    Eric Wajnberg
    Directeur adjoint du GDR CNRS 2155 Ecologie Comportementale
    I.N.R.A.
    37, Bld. du Cap. 06600 Antibes. France.
    Tel : (33-0) 4.93.67.88.92
    Fax : (33-0) 4.93.67.88.97
    e-mail : wajnberg AT antibes DOT inra DOT fr

    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~