Als made an interesting point that you should allocate memory from the heap if your object needs to persist beyond the scope in which it was created. In the code above, you don't need to allocate memory from heap at all. You can rewrite it like this:
#include
int a = 17;
int main(void)
{
int b = 18; //automatic stack memory
int c[1]; // allocating stack memory. sizeof(int) * 1
c[0] = 19;
printf("a = %d at address %x\n", a, &a);
printf("b = %d at address %x\n", b, &b);
printf("c = %d at address %x\n", c[0], c);
system("PAUSE");
return 0;
}
In fact, as part of the C99 standard (Variable-length array), you can use the [] operator to allocate dynamic space for an array on the stack just as you would normally do to create an array. You don't even need to know the size of the array at compilation time. The compiler will just adjust the esp register (for x86 machines) based on the requested allocation space and you're good to go.
