未定义的引用继承

undefined reference inheritance

本文关键字：继承 引用 未定义      更新时间：2023-10-16

我创建了基础Sprite类：

#ifndef SPRITE_H_
#define SPRITE_H_
#include<iostream>
#include<SDL2/SDL.h>
#include<SDL2/SDL_image.h>
class Sprite
{
public:
    Sprite(SDL_Texture* texture, int x, int y, int w, int h, SDL_Renderer* p_renderer);
    virtual ~Sprite();
    SDL_Rect getRect();
    SDL_Texture* loadImage(std::string file_path);
    void drawSprite();
    void setPosition(int x, int y);
    float getXpos();
    float getYpos();
private:
    SDL_Renderer* gRenderer;
    SDL_Texture* image;
    SDL_Rect rect;
    //for position update
    float x_pos;
    float y_pos;
};
#endif /* SPRITE_H_ */
    #include "Sprite.h"
Sprite::Sprite(SDL_Texture* texture, int x, int y, int w, int h, SDL_Renderer* p_renderer)
{
    gRenderer = p_renderer;
    image = texture;
    rect.x = x;
    rect.y = y;
    rect.w = w;
    rect.h = h;
    x_pos = x;
    y_pos = y;
}
Sprite::~Sprite()
{
    SDL_DestroyTexture(image);
}
float Sprite::getXpos()
{
    return x_pos;
}
float Sprite::getYpos()
{
    return y_pos;
}
SDL_Texture* loadImage(std::string file_path, SDL_Renderer* p_renderer)
{
    return IMG_LoadTexture(p_renderer, file_path.c_str());
}
void Sprite::drawSprite()
{
    SDL_RenderCopy(gRenderer, image, NULL, &rect);
}

接下来，我创建了Bird类，它使用Sprite类作为基础：

    /*
 * Bird.h
 *
 *  Created on: 1 maj 2016
 *      Author: Astral
 */
#ifndef BIRD_H_
#define BIRD_H_
#include "Sprite.h"
class Bird: public Sprite
{
public:
    Bird(SDL_Texture* texture, int x, int y, int w, int h, SDL_Renderer* p_renderer, float p_speed, float p_acceleration);
    virtual ~Bird();
    void updateBird(int x, int y);
    void handleInput();
private:
    float speed, acceleration;
};
#endif /* BIRD_H_ */
    #include "Bird.h"

Bird::Bird(SDL_Texture* texture, int x, int y, int w, int h, SDL_Renderer* p_renderer, float p_speed, float p_acceleration):Sprite(texture, x, y, w, h, p_renderer)
{
    speed = p_speed;
    acceleration = p_acceleration;
}
Bird::~Bird()
{
}
void Bird::updateBird(int x, int y)
{
    Sprite::setPosition(x, y);
}

现在我犯了一个错误，我不知道为什么：../src/Bird.cpp:18:对"Sprite:：setPosition（int，int）"的未定义引用

Sprite.cpp
1.
void Sprite::setPosition(int x, int y)
{
    x_pos = x;
    y_pos = y;
}
2.
SDL_Texture* loadImage(std::string file_path, SDL_Renderer* p_renderer)
　↓
SDL_Texture* Sprite::loadImage(std::string file_path)
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