How to identity processor architecture

[prabhu]

Hi Dear,

I just wanna to know my processor architecture(32bit or 64 bit) through 
c programming.

According to me the sizeof of pointer will give the result. Like below 
coding.

int main()
{
int *ptr;
printf("%d",sizeof(ptr));
}

If the result is 4 then it is 32 bit processor... If it is 8 then it is 
64 bit processor.

Please correct me if i am wrong... (I do not have system to check this.)

Any suggestion or help would be appreciated.

Thanks,
Prabhu