références non définies

Question

Linker erreur:

$ make 
g++ -Wall -g main.cpp SDL_Helpers.cpp Game.cpp DrawableObject.cpp `sdl-config --cflags --libs` -lSDL_mixer 
/tmp/ccdxzrej.o: In function `Game': 
/home/brett/Desktop/SDL/Game.cpp:16: undefined reference to `Player::Player(Game*)' 
/home/brett/Desktop/SDL/Game.cpp:16: undefined reference to `Player::Player(Game*)' 
collect2: ld returned 1 exit status 
make: *** [all] Error 1 

main.cpp:

#include "Game.h" 

int main() 
{ 
    Game g; 
    return 0; 
} 

Game.h:

#ifndef BRETT_GAME_H 
#define BRETT_GAME_H 

#include <cmath> 
#include "SDL.h" 
#include "SDL_Helpers.h" 
#include <vector> 

class DrawableObject; 

class Game 
{ 
public: 
    SDL_Surface * screen; 
    std::vector<DrawableObject*> sprites; 

    Game(); 
}; 

#endif 

Game.cpp:

#include "Game.h" 
#include "DrawableObject.h" 
#include "Player.h" 

Game::Game() 
{ 
    if (SDL_Init(SDL_INIT_VIDEO) != 0) 
     return; 

    atexit(SDL_Quit); 
    screen = SDL_SetVideoMode(640, 480, 0, SDL_DOUBLEBUF); 

    if (screen == NULL) 
     return; 

    sprites.push_back(new Player(this)); 

    while (true) 
    { 
     SDL_Event * event = NULL; 
     while(SDL_PollEvent(event) && event) 
     { 
      if(event->type == SDL_QUIT) 
       return; 
     } 

     SDL_LockSurface(screen); 

     for (uint32 i=0; i<sprites.size(); ++i) 
     { 
      sprites[i]->update(event); 
     } 

     SDL_FreeSurface(screen); 
     SDL_Flip(screen); 
    } 
} 

DrawableObject.h:

#ifndef DRAWABLE_OBJECT_H 
#define DRAWABLE_OBJECT_H 

#include "SDL.h" 
#include "SDL_Helpers.h" 

class Game; 

class DrawableObject 
{ 
public: 
    Game * const game; 

    DrawableObject(Game * const game_); 

    virtual void update(SDL_Event *event) = 0; 

}; 

#endif 

DrawableObject.cpp:

#include "DrawableObject.h" 
#include "Game.h" 

DrawableObject::DrawableObject(Game * const game_) 
    : game(game_) 
{ 

} 

Player.h:

#ifndef PLAYER_H 
#define PLAYER_H 

#include <cmath> 
#include "DrawableObject.h" 

class Player : public DrawableObject 
{ 
public: 
    Player(Game * const game); 

    void update(SDL_Event *event); 
}; 

#endif 

Player.cpp:

#include "Player.h" 
#include "Game.h" 

Player::Player(Game * const game) 
    : DrawableObject(game) 
{ 

} 

void Player::update(SDL_Event *event) 
{ 
    draw_circle(game->screen, 100, 100, 50, 0xff000000); 
} 

Answer 1

Vous êtes absent joueur .cpp dans votre ligne de compilation. Vous rencontrez une erreur de lien.

Answer 2

Pas un problème de dépendance circulaire (du moins, pas comme vous l'avez fait pour votre question). Vous avez oublié de compiler Player.cpp.