#include <iostream>
using namespace std;

#include "A.h"

int main()
{
    // Value of n cannot be changed.
    const int n = 7;

    cout << n << endl;

    // x data member is const.
    A a(2, 3);

    // Whole class is const.
    const A b(4, 5); 

    cout << a.x << " " << a.y << endl;
    cout << b.x << " " << b.y << endl;

    // x data member cannot be changed.
    a.y = 13;
    cout << a.x << " " << a.y << endl;

    // The following line is not legal 
    // because b is const.
    // b.y = 15;

    return EXIT_SUCCESS;
}

// Output:
// 7
// 2 3
// 4 5
// 2 13