C++ 为什么我的类仍然是抽象的?

问题描述

我确信这对我来说很简单，但我不明白为什么我的编译器认为我的一个类是抽象的.情况如下:

I'm sure its something simple on my part, but I can't figure out why my compiler thinks one of my classes is abstract. Here's the situation:

我有一个像这样的抽象基类:

I have an abstract base class like so:

class AnimatedDraw
{
public:
    virtual void Draw(sf::RenderWindow &window) = 0;
    virtual void Draw(sf::RenderWindow &window, sf::Shader shader) = 0;
    virtual void Update(sf::Clock &time) = 0;
};

我继承了它:

class ScreenLayer : public AnimatedDraw
{
public:
    ScreenLayer(void);

    virtual void Draw(sf::RenderWindow &window);

    virtual void Draw(sf::RenderWindow &window, sf::Shader &shader);

    virtual void Update(sf::Clock &clock);

    ~ScreenLayer(void);
};

供参考，ScreenLayer.cpp文件如下:

for reference, the ScreenLayer.cpp file is as follows:

#include "ScreenLayer.h"
ScreenLayer::ScreenLayer(void)
{
}
void ScreenLayer::Draw(sf::RenderWindow &window)
{
}
void ScreenLayer::Draw(sf::RenderWindow &window, sf::Shader &shader)
{
}
void ScreenLayer::Update(sf::Clock &clock)
{
}
ScreenLayer::~ScreenLayer(void)
{
}

然而，当我尝试使用我的派生类(即 AnimatedDraw *testDrawer = new ScreenLayer; )时，我的编译器抱怨 ScreenLayer 是抽象的.出于同样的原因，将 AnimatedDraw 更改为 ScreenLayer 也是无效的.我覆盖了基类上的所有抽象函数，不是吗?我不确定为什么它被视为抽象的.任何帮助将不胜感激

However, when I try to use my derived class (i.e. AnimatedDraw *testDrawer = new ScreenLayer; ) my compiler complains the ScreenLayer is abstract. Changing AnimatedDraw to ScreenLayer was also invalid for the same reason. I overwrote all the abstract function on my base class didn't I? I'm not sure why it's being seen as abstract. Any help would be appreciated

谢谢

推荐答案

你的基类声明在 sf::Shader 之后没有 & 符号:

Your base class declaration doesn't have an ampersand after sf::Shader:

virtual void Draw(sf::RenderWindow &window, sf::Shader shader) = 0;

派生类有，因此它是一个不同的重载函数.

The derived class has, hence it's a different overloaded function.

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