Programming and Graphics

118 Introduction to C++ Programming and Graphics

To circumvent this difficulty, we declare the variable in the second file as
external by issuing the statement:

extern int kokoras;

which reassures the compiler that the value of this variable will be supplied
externally.

As an example, the main program contained in the filekotoula.cc, and a
function namedkalabokiare implemented, respectively, as:

#include <iostream>

#include "kalaboki.h"

using namespace std;

int kokoras = 10;

int main()

{

kalaboki();

cout << kokoras << endl;

return 0;

}

and

using namespace std;

extern int kokoras;

void kalaboki()

{

kokoras++;

return kokoras;

}

The header file of the functionkalaboki.ccis:

#ifndef KALABOKIH

#define KALABOKIH

using namespace std;

extern int kokoras;

void kalaboki();

#endif