weird C program output

[Arun G Nair]

Hi,

Am a bit confused by the output of the this C program:

-------------------------------------------------------------ptr.c---
#include <stdio.h>

int
main()
{
    int *ptr, x;

    x = 2;
    ptr = &x;

    printf("x=%d, *ptr=%d, ptr=%p, &x=%p\n", x, *ptr, ptr, &x);

    *ptr++;
    printf("x=%d, *ptr=%d, ptr=%p, &x=%p\n", x, *ptr, ptr, &x);

    ++(*ptr);
    printf("x=%d, *ptr=%d, ptr=%p, &x=%p\n", x, *ptr, ptr, &x);

    return 0;
}

--------------------------------------------------------------------------

The output I get is this:

$ ./a.out
x=2, *ptr=2, ptr=0xbfbfece0, &x=0xbfbfece0
x=2, *ptr=-1077941020, ptr=0xbfbfece4, &x=0xbfbfece0
x=2, *ptr=750764012, ptr=0xbfbfece5, &x=0xbfbfece0
---------------------------------------------------------------------------

If ++(*ptr) is supposed to increment the value *ptr, then why is there a
change in memory address (0xbfbfece5) ?


Any ideas ? I know that am referring someone else's memory, but still..

-Arun