Defining a global variable in the header?

[PassTheGrape]

Hello, I have a variable named fSize in the header Structures.h and initialized it to 5:

#include "stdafx.h"
#include <iostream>
#include <string>
#include <iomanip>

extern int fSize = 5;

#ifndef Ammount_H
#define Ammount_H

struct Workers
{

..code...
..code...

};
#endif 

But when I go and implement this variable (through multiple files), I am given the error: fSize is ambiguous.

Example being implemented:

#include "stdafx.h"
#include <iostream>
#include <string>
#include <iomanip>
#include "Structures.h"
using namespace std;

Workers emp[fSize];
int c;
double Rate[fSize], Pay[fSize];

In the instance above, I am thrown acouple errors:
error C2872: 'fSize': ambiguous symbol
d:...Structures.h(8): note: could be 'int fSize'

How can I fix this problem?

[Kevin C]

Use:

extern int fSize;

[AbstractionAnon]

Lines 8 and 10 in the second snippet are not valid C++, although some compilers allow this.
Compliant C++ requires that array sizes are known at compile time.

[jlb]

have a variable named fSize in the header Structures.h

This variable should really be a const and it should not be initialized in the header. Something like:

// In the header file.
extern const int fSize;

// In one and only one of your source files.
const int fSize = 5;

All of the other source files will include the header to have access to this variable.