#include <iostream>                    // Ex01
using namespace std;
bool x;                                // global declaration in a source file
int main () {
    short y;                        // local (automatic) declaration in block
    cout << "x:" << x << endl;        // use of global variable
    cout << "y:" << y << endl;        // use of local variable
    int z;                            // local declaration anywhere in block
    cout << "z:" << z << endl;        // use of local variable
    {
        long y;                        // nested local redeclaration, hide previous y
        cout << "y:" << y << endl;    // use of local variable
        double z;                    // nested local redeclaration, hide previous z
        cout << "z:" << z << endl;    // use of local variable
    }
}