//
// This is example code from Chapter 8.8 "Drill" of
// "Programming -- Principles and Practice Using C++" by Bjarne Stroustrup
//

#include <iostream>

//------------------------------------------------------------------------------

using std::cout;

namespace X
{
    int var = 0;

    void print()
    {
        cout << var << '\n';
    }
};

//------------------------------------------------------------------------------

namespace Y
{
    int var = 0;

    void print()
    {
        cout << var << '\n';
    }
};

//------------------------------------------------------------------------------

namespace Z
{
    int var = 0;

    void print()
    {
        cout << var << '\n';
    }
};

//------------------------------------------------------------------------------

int main()
{
    X::var = 7;
    X::print();    // print X's var
    using namespace  Y;
    var = 9;
    print();       // print Y's var
    {    
        using Z::var;
        using Z::print;
        var = 11;
        print();   // print Z's var
    }
    print();       // print Y's var
    X::print();    // print X's var
}

//------------------------------------------------------------------------------