Error when using namespaces - class not declared

Question

I'm new to C++ and using namespaces and I can't see what I'm doing wrong here. When I compile the code below, I get the error:

error: 'Menu' has not been declared

Here is my header file Menu.hpp

#ifndef MENU_H //"Header guard"
#define MENU_H

namespace View
{
class Menu
    {
    void startMenu();
    };
}
#endif

and my Menu.cpp:

#include "stdio.h"
using namespace std;

namespace View
{
 void Menu::startMenu()
    {
    cout << "This is a menu";
    }
}

#include "Menu.hpp" in your Menu.cpp.

Mark Garcia
– Mark Garcia

2013-08-25 06:04:30 +00:00
Commented Aug 25, 2013 at 6:04 — Mark Garcia
– Mark Garcia, Commented Aug 25, 2013 at 6:04

Community · Accepted Answer · 2017-05-23 12:08:34Z

4

You missed including the header file which defines the class.

Menu.cpp:

#include "Menu.hpp"

Each translation unit is compiled separately by the compiler and if you do not include the header file in Menu.cpp, there is no way for the compiler to know what Menu is.

edited May 23, 2017 at 12:08

CommunityBot

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answered Aug 25, 2013 at 6:06

Alok Save

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1 Comment

Dawson Over a year ago

Thanks, I didn't realise each class had to include it's own header.

Saksham · Accepted Answer · 2013-08-25 06:05:26Z

3

You will have to include header Menu.hpp in your cpp file Menu.cpp like

#include "Menu.hpp"

answered Aug 25, 2013 at 6:05

Saksham

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