Author: Miguel A. Ballicora
Date: 08:50:28 12/27/01
Go up one level in this thread
On December 27, 2001 at 11:19:35, José Carlos wrote:
>On December 27, 2001 at 10:20:58, Miguel A. Ballicora wrote:
>
>>On December 27, 2001 at 09:02:00, José Carlos wrote:
>>
>>>
>>> When things like these happen, I don't know whether it is the compiler that
>>>doesn't work or I'm losing my mind. Yesterday I added this piece of code:
>>>
>>>for (i=0;i<PosActual->NumPeonesB;i++)
>>>{
>>> cCol=Columna(g_iPL_PB[i]);
>>> cFil=Fila(g_iPL_PB[i]);
>>> if (cFil>Retrasado(uPeonesB[cCol]))
>>>uPeonesB[cCol]=(ParteAvanzada(uPeonesB[cCol]))|(unsigned int)(cFil);
>>> if (cFil<Avanzado(uPeonesB[cCol]))
>>>uPeonesB[cCol]=(cFil<<16)|ParteRetrasada(uPeonesB[cCol]);
>>>}
>>>for (i=0;i<PosActual->NumPeonesN;i++);
>>>{
>>> cCol=Columna(g_iPL_PN[i]);
>>> cFil=Fila(g_iPL_PN[i]);
>>> if (cFil<Retrasado(uPeonesN[cCol]))
>>>uPeonesN[cCol]=(ParteAvanzada(uPeonesN[cCol]))|(unsigned int)(cFil);
>>> if (cFil>Avanzado(uPeonesN[cCol]))
>>>uPeonesN[cCol]=(cFil<<16)|ParteRetrasada(uPeonesN[cCol]);
>>> i++;
>>>}
>>>
>>> which fills two lists with information for pawn eval. When I run it, then it
>>>performed an unhandled exception. I traced it and, to my surprise, when
>>>initializing i in the second loop (exactly after executing the second for), the
>>>value of i was 8!!!
>>
>>if PosActual->NumPeonesN is 7, when the first loop finishes i should be 8.
>
> Nope. It is 8 _after_ executing the sencond 'for' with F10.
Ok, now I understand. Tracing sometimes is tricky when all the optimizations
are 'ON'. Did you try with all the optimizations 'OFF'?. It looks like i was not
initilialized "yet" but the important thing is that i has the right value the
first time is needed.
Try this in the second loop with the optimizations ON:
for (i=0;i<PosActual->NumPeonesN;i++)
{
if (i < 0 || i >= PosActual->NumPeonesN)
printf("n\Error, i=%d\n",i);
exit(EXIT_FAILURE);
}
printf("trace i: %d\n",i);
...
}
I still do not understand why you do i++ at the end of the second loop.
As far as I can see, that will skip several variables to be initialized.
You should be able to see it with printf("trace i:...
I wonder if that is the problem.
Saludos,
Miguel
>
>>I do not see anything wrong with that. The loop breaks when
>>i<PosActual->NumPeonesN is no longer true, in other words, 8 or bigger.
>>
>>> I changed i for other variable; same thing. I tried to loop from
>>>PosActual->NumPeonesN-1 down to zero; then i got a very big value instead of 7
>>>-there were 8 pawns- (i is an integer).
>>
>>I'd like to see the actual loop control, if you have
>>for (i=PosActual->NumPeonesN-1; i>=0; i--)
>>then the loop breaks when i is lower than 0, i.e. -1.
>>What kind of integer is i? unsigned? if that is true -1 underflows and goes to
>>the maximum positive number that you gan get. The loop will never end and can
>>create all sort of troubles that you can imagine.
>>The other possibility is that you look at i as unsigned in the debugging session
>>giving you a big number.
>
> i is signed int.
>
>>In the second loop there are things that I do not understand:
>>
>>for (i=0;i<PosActual->NumPeonesN;i++);
>> /* ^
>> * |
>> * I do not think you intended to add this semicolon here!!!!
>> */
>
> It is a typo made when removing comments to post it here. Not in my code.
>
> José C.
>
>>{
>> cCol=Columna(g_iPL_PN[i]);
>> cFil=Fila(g_iPL_PN[i]);
>> if (cFil<Retrasado(uPeonesN[cCol]))
>> uPeonesN[cCol]=(ParteAvanzada(uPeonesN[cCol]))|(unsigned int)(cFil);
>> if (cFil>Avanzado(uPeonesN[cCol]))
>> uPeonesN[cCol]=(cFil<<16)|ParteRetrasada(uPeonesN[cCol]);
>>
>> /* Why you update i here at the end if you do it at the top? */
>>
>> i++;
>>
>>}
>>
>>I hope this helped.
>>
>>Saludos,
>>Miguel
>>
>>
>>> Finally, I had to do a 'while' instead of a 'for' and it worked perfectly.
>>> Can anyone tell me if I'm doing something wrong in the above code?
>>>
>>> Thanks in advance.
>>>
>>> José C.
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