Why function does not know the array size?

Question

If I write

int main()
{
    int a[100] = {1,2,3,4,};
    cout<

        

Answer 1

This isn't working because sizeof is calculated at compile-time. The function has no information about the size of its parameter (it only knows that it points to a memory address).

Consider using an STL vector instead, or passing in array sizes as parameters to functions.

This was answered by Marcel Guzman in Calculating size of an array!