错误 C2504：基类未定义

Question

我之前多次遇到这个错误并最终找到了解决方案，但是这个让我很难过。我有一个由“Player”类继承的“Mob”类。这是 Mob.h：

 #pragma once
#include "PlayState.h"
#include "OmiGame/OmiGame.h"
#include "resources.h"

class PlayState;

class Mob
{
private:
    int frames;
    int width;
    int height;
    int time;

    sf::Texture textureL;
    sf::Texture textureR;
    Animation animationL;
    Animation animationR;
    AnimatedSprite sprite;
    bool moveLeft;
    bool moveRight;
    bool facingRight;

public:
    void createMob(std::string l, std::string r, int frames, int width, int height, int time, int x, int y);

    void updateMob(omi::Game *game, PlayState *state);
    void drawMob(sf::RenderTarget &target);

    void setLeft(bool b) { moveLeft = b; }
    void setRight(bool b) { moveRight = b; }
    bool isLeft() { return moveLeft; }
    bool isRight() { return moveRight; }

    sf::Vector2f getPosition() { return sprite.getPosition(); }
};

这是 Player.h，到目前为止它非常简单：

 #pragma once
#include "OmiGame/OmiGame.h"
#include "PlayState.h"
#include "Mob.h"
#include "resources.h"

class PlayState;
class Mob;

const int playerFrames = 8;
const int playerWidth = 16;
const int playerHeight = 48;
const int playerTime = 50;
const int playerX = 200;
const int playerY = 200;

class Player : public Mob
{ //the error occurs at this line//
public:
    Player();
    void update(omi::Game *game, PlayState *state);
    void draw(sf::RenderTarget &target);
};

而且，您可能会猜到，这是错误：

 error C2504: 'Mob' : base class undefined   player.h

我已经转发了声明的暴民，我希望修复了任何循环依赖。请问有人可以帮我吗？

原文由 Greg Treleaven 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

前向声明对 class Player : public Mob 没有帮助，因为编译器需要完整的继承定义。

所以很可能你在 Mob.h 中包含的一个是引入 Player.h ，然后将 Player 置于 Mob 之前，从而触发错误。

原文由 TheUndeadFish 发布，翻译遵循 CC BY-SA 3.0 许可协议