sizeof array

Hi,
Was trying this program

Code:

---

#include<stdio.h>

int retsize( int a[] );

int main()
{
    int arr[]={1,2,3,4};

    printf(" size = %d \n",sizeof(arr));
    printf(" size = %d \n",retsize(arr));

    return 0;
}

int retsize (int arr[])
{
    return sizeof(arr);
}

---

The answer im getting is
size = 16
size = 4

i wonder why the function is not returning 16 too.
please shed some light. and how do i correct it

Thanks
MAx

It is not possible to pass an array to a function. Instead, a pointer to the first element is passed (and as you see, pointers are four bytes).

And if you actually want to use the size of an array when it has been passed to a function, you need to pass the original size from the calling code - that is, add another parameter to the function that indicates the size.

--
Mats