Problems with my first class.

main.cpp

Code:

---

#include <iostream>

#include "Memoryx.cpp"


int main(){
    Memoryx::que();
    return 1;
}

---

Memoryx.cpp

Code:

---

#include "Memoryx.h"

Memoryx::que(){
        printf("aaa");
}

---

Memoryx.h

Code:

---

#ifndef __MEMORYX_H__
#define __MEMORYX_H__

class Memoryx{
      public:
          que();
};

#endif

---

Error:

Code:

---

Compiler: Default compiler
Building Makefile: "C:\Documents and Settings\robdah01\Skrivbord\classtest\Makefile.win"
Executing  make...
make.exe -f "C:\Documents and Settings\robdah01\Skrivbord\classtest\Makefile.win" all
g++.exe -c main.cpp -o main.o -I"C:/Dev-Cpp/lib/gcc/mingw32/3.4.2/include"  -I"C:/Dev-Cpp/include/c++/3.4.2/backward"  -I"C:/Dev-Cpp/include/c++/3.4.2/mingw32"  -I"C:/Dev-Cpp/include/c++/3.4.2"  -I"C:/Dev-Cpp/include" 

In file included from main.cpp:3:
Memoryx.h:6: error: ISO C++ forbids declaration of `que' with no type

main.cpp: In function `int main()':
main.cpp:8: error: cannot call member function `int Memoryx::que()' without object

make.exe: *** [main.o] Error 1

Execution terminated

---

This is my first class, i get an error while compiling.
How much i try to figure out why this isn't working.
I want to learn how to write file inclusions, and classes.

Well, one problem is that you gailed to declare and define Memoryx::que with a return type, e.g., void. Another problem is that Memoryx::que is a non-static member function, so it should be called from a Memoryx object. You also should #include <cstdio> in Memoryx.cpp in order to use printf, which should be qualified as std::printf.

By the way, names that begin with an underscore followed by an uppercase letter, or that contain consecutive underscores, are reserved to the (compiler and standard library) implementation for any use. Therefore, instead of using __MEMORYX_H__ for the header inclusion guard, use say, MEMORYX_H_.

Also, the global main function normally returns 0 upon successful execution.

Quote:

---

Originally Posted by laserlight

Well, one problem is that you gailed to declare and define Memoryx::que with a return type, e.g., void. Another problem is that Memoryx::que is a non-static member function, so it should be called from a Memoryx object. You also should #include <cstdio> in Memoryx.cpp in order to use printf, which should be qualified as std::printf.

By the way, names that begin with an underscore followed by an uppercase letter, or that contain consecutive underscores, are reserved to the (compiler and standard library) implementation for any use. Therefore, instead of using __MEMORYX_H__ for the header inclusion guard, use say, MEMORYX_H_.

Also, the global main function normally returns 0 upon successful execution.

---

New code, but still, it's not working :/

main.cpp

Code:

---

#include <iostream>
#include <cstdio>
#include "Memoryx.cpp"


int main(){
    Memoryx::que();
    return 0;
}

---

Memoryx.cpp

Code:

---

#include <cstdio>
#include "Memoryx.h"

static void Memoryx::que(){
        std::printf("aaa");
}

---

Memoryx.h

Code:

---

#ifndef MEMORYX_H_
#define MEMORYX_H_

class Memoryx{
      public:
        static void que();
};

#endif

---

Error:

Code:

---

Compiler: Default compiler
Building Makefile: "C:\Documents and Settings\robdah01\Skrivbord\classtest\Makefile.win"
Executing  make...
make.exe -f "C:\Documents and Settings\robdah01\Skrivbord\classtest\Makefile.win" all
g++.exe -c Memoryx.cpp -o Memoryx.o -I"C:/Dev-Cpp/lib/gcc/mingw32/3.4.2/include"  -I"C:/Dev-Cpp/include/c++/3.4.2/backward"  -I"C:/Dev-Cpp/include/c++/3.4.2/mingw32"  -I"C:/Dev-Cpp/include/c++/3.4.2"  -I"C:/Dev-Cpp/include" 

Memoryx.cpp:4: error: cannot declare member function `static void Memoryx::que()' to have static linkage

make.exe: *** [Memoryx.o] Error 1

Execution terminated

---

you should not include cpp file - you include h file

then - you compile and link both cpp files together

Thank you, problem solved!
Code:

main.cpp

Code:

---

#include <iostream>
#include <cstdio>
#include <conio.h>
#include "Memoryx.h"


int main(){
    Memoryx::que();
    getch();
    return 0;
}

---

Memoryx.cpp

Code:

---

#include <cstdio>
#include "Memoryx.h"

void Memoryx::que(){
        std::printf("aaa");
}

---

Memoryx.h

Code:

---

#ifndef MEMORYX_H_
#define MEMORYX_H_

class Memoryx{
      public:
        static void que();
};

#endif

---

You should know that you have no class objects there. Becuase you have only static functions, your class is really nothing more than a namespace. There's not really any OOP going on here.