Thread: header file help

I can't seem to get a simple header file to work, when my teacher does it, it seems to work fine. Here is a short piece of code that I can't get to compile.

------------------------
//defines.h
#ifndef DEFINES_H
#define DEFINES_H

void foo();
void bar();

int nNum;

#endif
-------------------------

-------------------------
//driver.cpp
#include <iostream>
#include "defines.h"

using namespace std;

main()
{
foo();
bar();

cout << nNum << endl;

return (0);
}
-------------------------

________________
//process.cpp
#include <iostream>
#include "defines.h"

using namespace std;

void foo()
{
nNum = 5;

return;
}

void bar()
{
nNum += 1;

return;
}
---------------------------

Any help would be great, thanks

Don't declare the variables in the header file. Thats just wrong.