Destructor not finding my namespace method-CodePudding

main.cpp:

#include "headerone.hpp"

int main() {
    menus::menu();
}

headerone.hpp:

#pragma once

#include "headertwo.hpp"

namespace menus {
    void menu() {
       object instance;
    }
}

headertwo.hpp:

#pragma once

#include "headerone.hpp"

class object {
public:
    object() {
       method();
    }

    void method() {
        int x; /* do something */
    }

    ~object() {
        menus::menu();
    }
};

I get an error in the deconstructor saying that menu namespace cannot be found.

Error C2653 'menu': is not a class or namespace name

CodePudding user response：

The menu() function should only be declared in the header file. The definition should be in its associated .cpp source file.

The headerone.hpp file should look like this:

#pragma once

namespace menus {

void menu();

} // menus

The headerone.cpp file should look like this:

#include "headerone.hpp"
#include "headertwo.hpp"

namespace menus {

void menu() {
   object instance;
}

} // menus

One of the areas that many good C books omit are how source files, header files, and projects should be put together. There is one good — albeit rather long in the tooth (but still relevant) — book called Large-Scale C Software Design by John Lakos which discusses project layout and suggested implementation in great detail.

He also has a more recent book in two volumes called Large-Scale C , which is not a replacement for the earlier book. Rather it has an even broader and more ambitious scope for software development. Volume I is Process and Architecture, and Volume II is Design and Implementation.

CodePudding user response：

You have cyclic dependency in your program.

You can solve this by using source files(.cpp) in addition to header files(.hpp) as shown below:

headerone.hpp

#pragma once

#include "headertwo.hpp"

namespace menus {
    void menu(); //this is a declaration
}

headerone.cpp

#include "headerone.hpp"
namespace menus
{
//this is a definition
void menu() {
       object instance;
}
}

headertwo.hpp

#pragma once

//no need to include headerone.hpp here

class object {
public:
    object() {
       method();
    }

    void method() {
        int x; /* do something */
    }

    ~object();//this is a declaration
};

headertwo.cpp

#include "headertwo.hpp"
#include "headerone.hpp"
object::~object() {
        menus::menu();
}

main.cpp

#include "headerone.hpp"
#include "headertwo.hpp"
int main() {
    menus::menu();
}

The output of the above modified program can be seen here.