Making Global Struct in C++ Program
- by mosg
Hello world!
I am trying to make global structure, which will be seen from any part of the source code. I need it for my big Qt project, where some global variables needed. Here it is: 3 files (global.h, dialog.h & main.cpp). For compilation I use Visual Studio (Visual C++).
global.h
#ifndef GLOBAL_H_
#define GLOBAL_H_
typedef struct TNumber {
int g_nNumber;
} TNum;
TNum Num;
#endif
dialog.h
#ifndef DIALOG_H_
#define DIALOG_H_
#include <iostream>
#include "global.h"
using namespace std;
class ClassB {
public:
ClassB() {};
void showNumber() {
Num.g_nNumber = 82;
cout << "[ClassB][Change Number]: " << Num.g_nNumber << endl;
}
};
#endif
and main.cpp
#include <iostream>
#include "global.h"
#include "dialog.h"
using namespace std;
class ClassA {
public:
ClassA() {
cout << "Hello from class A!\n";
};
void showNumber() {
cout << "[ClassA]: " << Num.g_nNumber << endl;
}
};
int main(int argc, char **argv) {
ClassA ca;
ClassB cb;
ca.showNumber();
cb.showNumber();
ca.showNumber();
cout << "Exit.\n";
return 0;
}
When I`m trying to build this little application, compilation works fine, but the linker gives me back an error:
1>dialog.obj : error LNK2005: "struct TNumber Num" (?Num@@3UTNumber@@A) already defined in main.obj
Is there exists any solution?
Thanks.
