Visual C++:编译器错误C4430

Question

Game.h的代码:

#ifndef GAME_H
#define GAME_H

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

#endif

错误:

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

我究竟做错了什么？

Answer 1

你需要做两件事:

• #include <string>
• 将类型更改为const static std::string QUIT_GAME(添加std::)

Answer 2

以下是解决问题所需的内容:

1.包含字符串头文件:
#include <string>

2.前缀string及其命名空间: const static std::string QUIT_GAME;

或插入一份using声明:

#include <string>
using std::string;

3.为变量分配空间
因为您static在类中声明它,所以必须在代码中的某处定义它:
const std::string Game::QUIT_GAME;

4.用值初始化变量 因为你声明了字符串const,你需要将它初始化为一个值(或者它将保持一个常量空字符串):
const std::string Game::QUIT_GAME = "Do you want to quit?\n";