Globali.cpp

#include <iostream>
using namespace std;

int a=5;

void f() {

a=a+1;
cout << "a in f :" << a << " (" << &a << ")" << endl;
return;

}

main() {

cout << "a in main:" << a << " (" << &a << ")" << endl;
f();
cout << "a in main:" << a << " (" << &a << ")" << endl;

}