Question

In the below program, as far as in my knowledge once we allocate some memory then if we are chaging the address from
ptr to ptr++, then when we are calling free with ptr i.e free(ptr).
Then the program should crash.
But in this program works fine.
How it works?
I am using Code::Bocks in Windows XP.
Please help me.

int main()
{
    int *ptr;
    ptr = malloc(1);
    *ptr = 6;
    printf("The value at *ptr = %d \n", *ptr);
    ptr++;      //Now ptr is address has been changed
    free(ptr); // Program should crash here
    ptr = NULL;
    /* *ptr = 5;*/ // This statement is crashing
    return 0;
}

Answer 1

Absence of a crash does not necessarily mean your code is fine. On another platform, it will probably crash.
BTW: you should rather malloc(sizeof(int))