Find size of array without using sizeof

Question

I was searching for a way to find the size of an array in C without using sizeof and I found the following code:

int main ()
{
    int arr[100];         


        

Answer 1

int arry[6]={1,2,3,4,5,6} //lets array elements be 6, so... size in byte = (char*)(arry+6)-(char *)(arry)=24;