Why function does not know the array size?

Question

If I write

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

        

Answer 1

You get 400 the first time because you are passing only sizeof(a), not sizeof(a)/sizeof(a[0]), to cout. You need to wrap that calculation with parenthesis to get the correct value outputted, ie:

cout << (sizeof(a)/sizeof(a[0])) << endl;

For the second time, you should be getting 2, 4, or 8 (depending on architecture), definately not 400, since you are essentially outputting this:

cout << sizeof(int*) << endl;

Where the size of a generic pointer is always a fixed value.