Question

I was just looking into the memory allocation of a program in C. I know that all the global and static variables are stored in a heap. Also, the stack stores all the function calls. I do have one doubt here though. Say I am calling the following function:

int ret;
int num = 10;
int arr[3] = {1,2,3};
int *ptr = &arr[0];
ret = giveNumber(num, ptr);

Here, I read that the parameters of the function call giveNumer() would also be stored in the same stack. But in what order will they be stored? If I popped the top of stack, which parameter will be popped first, num or ptr?

Answer 1

I know that all the global and static variables are stored in a heap.
No, thats not true.
As per the standard they are stored in implementation defined memory regions, typically the Data segment and the BSS.

If I popped the top of stack, which parameter will be popped first, num or ptr
The order of evaluation of arguments to a function is Unspecified.
So it depends on your compiler implementation. An compiler might evaluate the arguments from:

• Left to Right or
• Right to Left or
• Any other random order

So the behavior & order you see would depend on this.