Visual C++: Compiler Error C4430

Question

The code of Game.h:

#ifndef GAME_H
#define GAME_H

class Game
{
    public:
        const static string QUIT_GAME; // line 8
        virtual void playGame() = 0;
};

#endif

The error:

game.h(8): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
game.h(8): error C2146: syntax error : missing ';' before identifier 'QUIT_GAME'
game.h(8): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

What am I doing wrong?

Solution 1

Here is what you need to fix your issues:

1. Include the string header file:
#include <string>

2. Prefix string with its namespace: const static std::string QUIT_GAME;

or insert a using statement:

#include <string>
using std::string;

3. Allocate space for the variable
Since you declared it as static within the class, it must be defined somewhere in the code:
const std::string Game::QUIT_GAME;

4. Initialize the variable with a value
Since you declared the string with const, you will need to initialize it to a value (or it will remain a constant empty string).:
const std::string Game::QUIT_GAME = "Do you want to quit?\n";

Solution 2

You need to do two things:

• #include <string>
• Change the type to const static std::string QUIT_GAME (adding std::)

Solution 3

#include <string>
...
const static std::string QUIT_GAME;

Solution 4

Missing the #include<string>

and it's std::string

View more solutions

Comments

[Adam Rosenfield]

You should never put a using statement in a header file. It irreversibly pollutes the namespace of any file that includes.

[Thomas Matthews]

Actually one more thing: initialize the variable. The const specifier is the kicker here. If the variable is not initialized, it will be a constant empty string. This has uses, but I don't think it is what the OP wanted.

[Tyler McHenry]

Note that you cannot initialize a string (even a constant static string) inside the class declaration. There must be a separate definition statement (of the form const std::string Game::QUIT_GAME = "Whatever";) inside the corresponding source (.cpp) file. Edit: Just saw your answer which explains this in detail below, and upvoted it.

[Tyler McHenry]

Don't use using in header files. Very bad juju. Otherwise, great, comprehensive answer.