C++ compilation problem

Question

Pretty much forgot how to code C++ at all. Anyway, here is the problem.

I am trying to load a class defined in a .cpp file I wrote myself.

In the main function:

... ...
 #include "loader.h"
... ...
 model load_model("TechnologyEnterpriseFacility_Day_Gregor/
               TechnologyEnterpriseFacility_Gregor.model");

the header file looks like this:

 #ifndef LOADER_H_
 #define LOADER_H_

 class model
 {
   public:
    int textures [];
    float vertices[][3];
    float triangles[][13]; 
    model(const char*); // constructor
 };

 #endif /* LOADER_H_ */

and here is the .cpp file:

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
#include <typeinfo>
#include "loader.h"

using namespace std;

model::model(const char* filename)
{
    ... ...

When I compile the main function, I got error message:

gcc -o glrender glrender.cpp -lglut
/tmp/cc3sWIgb.o: In function `__static_initialization_and_destruction_0(int, int)':
glrender.cpp:(.text+0x11b): undefined reference to `model::model(char const*)'
collect2: ld returned 1 exit status

comments and ideas are welcomed, thanks.

Answer 1

You need to supply the implementation file along with the header file. Either directly import it into your main program:

#include "implementation.cpp";

Or compile it separately with the compiler:

myCompiler -flags main.cpp implement.cpp

Either would work, but the latter is more maintainable and professional.

Answer 2

Didn't you forget to insert model.cpp in your compilation line ?

gcc -o glrender glrender.cpp model.cpp -lglut