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Top Forums UNIX for Dummies Questions & Answers portability of int arrays from 32 to 64 bit systems Post 302337204 by German1234 on Thursday 23rd of July 2009 03:21:58 PM

07-23-2009

Registered User

portability of int arrays from 32 to 64 bit systems

Dear All,
I'm porting my scientific program from 32 to 64 bit system
(use gcc, CentOS) and feel myself absolutely confused
after reading general internet advices for that. Could you help me,
please.

The question is:
can I use "old style" on 64 bit:
--------
int * myIntArray;
myIntArray = malloc (sizeof(int)*100000);
for (i=0;i<100000;i++)
myIntArray [i] = i*i;
int j=250;
int b=myIntArray [j];
--------

or should I use a more complicated construction like
--------
for (i=0;i<100000;i++)
myIntArray [(size_t) (i)] = i*i;
int j=250;
int b=myIntArray [(size_t) (j)];
--------
in this simple case throughout the code? Or that all is wrong?
And what should I do with arrays of doubles?

Trivial compilation on 64 bit system of my old code written for 32 bits
gives an executable file which can run, but shows numerical instability, and I'm trying to find the reason...

Thank you very much in advance!
Regards,
German

German1234

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