C++ 从基类调用派生类函数

Question

我不确定如何从基类调用派生类函数而不会出现某种错误，这是我尝试使用的代码的框架...

class DiceGame{
public:
    virtual void play(){
        // Trying to call the derived class
        // Knockout's play function in here
        // I've been trying this

        DiceGame *game = new Knockout;
        game->play();

        // But it gives me a memory error
    }

class Knockout : public DiceGame{
    void play(){
        // This has the stuff I want to call
    }

main(){
    DiceGame *game = new DiceGame();
    game->play();
}

我已经尝试过 Knockout 类的前向声明，但这也给了我一个不完整的前向声明错误，有什么建议吗？

Answer 1

class DiceGame{
public:
    virtual void play() = 0;
};

class Knockout : public DiceGame{
public:
    virtual void play() { // Replace "virtual" with "override" here if your compiler supports "override" keyword.
        // This has the stuff I want to call
    }
};

int main()
{
    DiceGame *game = new Knockout();
    game->play();
    return 0;
}