// You can think of there being two sorts of arrays.
//
// One, like alpha, where the entire array is local to the function.
// The other, like beta, where only a pointer to the data is local
// to the function.  The data that it points to lives elsewhere.
//
// Complicating the issue is the fact that the name of an array,
// like alpha, can be treated as a pointer.  That’s how we can
// call show() with alpha as an argument.  alpha, which is the name
// of an array, is converted into the pointer ptr.

#include <iostream>

using namespace std;

// Show an array of data.  You have to pass the length, because C++ doesn’t
// know the length of a C-style array.

void show(int *ptr, int length) {
    // cout << "size of ptr: " << sizeof(ptr) << '\n';
    for (int i=0; i<length; i++)
	cout << ptr[i] << ' ';
    cout << '\n';
}

int main() {
    int alpha[20];
    int *beta = new int[20];

    for (int i=0; i<20; i++)
	alpha[i] = beta[i] = i*i;

    show(alpha, 20);
    show(beta, 20);

    // cout << "size of alpha: " << sizeof(alpha) << '\n';
    // cout << "size of beta:  " << sizeof(beta) << '\n';

    delete[] beta;
    return 0;
}