Question

I’m fighting with memory managment right now. It’s verry funny for me 🙂

Here is simple app which I wrote. I can allocate memory in two ways.

int main (int argc,  const char * argv[])
{
    int *x;
    int *z;

    x = malloc(sizeof(int));
    z = (int *)sizeof(int);

    free(x);
    free(z);
}

Is there any difference between the ways of memory allocating used in the code above ?

Answer 1

The second line doesn’t allocate any memory, it’s the equivalent of

z=(int *)4;

ie, z will point to the (unallocated and most likely non-existant) (virtual) memory at address 4. If you do something like:

*z=0;

your program will crash to an access violation.