Help with Borland & Linking

Hello...this is my first time posting here, so if I screw up the code tags or something....:rolleyes:

Okay, I'm having trouble getting multiple files to compile with Borland C++Builder 4.0 I followed my school textbook example, but it doesn't give compiler specific instructions. I've tried adding all the files to a project, but I get this error:

[Linker Error] Unresolved external 'GetSum(int, int)' referenced from C:\PROGRAM FILES\BORLAND\CBUILDER4\PROJECTS\FUNCTION\FUNCTION .OBJ

Here is the code:

Code:

---

//main.cpp

#include <iostream.h>
#include <conio.h>
#include "test.h"

int main()
{
        int num1=5;
        int num2=5;
        int sum;

        sum=GetSum(num1,num2);
       
        cout << sum;

        getch();
        return 0;
}

---

Code:

---

//getsum.cpp
#include "test.h"

int GetSum(int num1, int num2)
        {
        int sum;
        sum=num1+num2;
        return sum;
        }

---

Code:

---

//test.h
#ifndef SUM

int GetSum(int num1, int num2);

#define SUM
#endif

---

Is there a problem with my code, or am I not doing something to compile or link it right? If anyone has experience with C++Builder 4, I could really use your help with this. Thanks.

The code seems fine, so the error lies in the linking. You said you added the files to a project, so I see no reason why it shouldn't work though...

you simply forgot to define SUM in your main.cpp:

Code:

---

  #define SUM

---

because a compile time, because the macro SUM isn't define, the function GetSum isn't compiled!!

Quote:

---

Originally posted by xmdvp
you simply forgot to define SUM in your main.cpp:

Code:

---

  #define SUM

---

because a compile time, because the macro SUM isn't define, the function GetSum isn't compiled!!

---

Nope! Notice the n in #ifndef meaning "if not defined". The function declaration is included if SUM is not defined.

Also, the error he gets is "unresolved external" which appears if you have the declaration but not the definition. If you miss the declaration, you get an "undeclared identifier" message or something.

Does anyone else have some suggestions that I could try to get this program working? It's very hard trying to continue learning C++ when you can't have multiple file programs...I can't compile half of the examples, and my teacher never taught us anything about using C++Builder4 except making a new project and hitting the compile button.

At this point, I'm open to any ideas or suggestions. Thank you.