// Example global.cpp

// Using a global variable.

// This modern include file syntax
// will be explained later.  Here
// including stdlib.h is not 
// necessary.

#include <iostream>
using namespace std;

int sum = 0;

int main()
{
    void update(int);

    update(5);
    update(8);
    cout << sum << endl;

    return EXIT_SUCCESS;
}

void update(int n)
{
    sum += n;
}

// Output:
13