Diff Between Call By Reference And Call By Pointer [duplicate]

Answer 1

In your example, there is no difference.

In C++ reference is implemented using pointers.

Edit: for those who believe reference can't be NULL:

int calc(int &arg)
{
    return arg;
}

int test(int *arg)
{
    return calc(*arg);
}

Guess, what will be the result for test(0)?