C++：工厂设计，无法在矢量上push_back

C++: factory design, can't push_back on vector

本文关键字：push back 工厂 C++      更新时间：2023-10-16

我目前正在为一个学校项目设计一个用c++编写的电子游戏。我们被建议使用抽象工厂设计来创建对象。

当玩游戏时，我想将对象(玩家，敌人，武器等)存储在一个实体(超类)指针向量中。
我在类GameLogic中定义关卡，但当我尝试用派生类填充矢量时，有时会出现错误，有时不会。在这个例子中，我添加了一些敌人，加速道具和生命值道具。SpeedPowerUp和HealthPowerUp是一样的，只是名称不同。
但添加一个HealthPowerUp工作，添加一个SpeedPowerUp不工作…

这些是我的代码片段:

普遍
typedef vector <Entitie*> container;
typedef vector <Entitie*>::iterator iter;

继承结构
class SDLSpeedPowerUp: public CDS::SpeedPowerUp....
class SpeedPowerUp: public CDS::PowerUp....
class PowerUp: public CDS::Entitie....
class SDLHealthPowerUp: public CDS::HealthPowerUp....
class HealthPowerUp: public CDS::PowerUp....
class SDLEnemy: public CDS::Enemy....
class Enemy: public CDS::Vehicle....

sdlfactory.h(部分代码)

class SDLFactory: public CDS::AbstractFactory {
public:
SDLFactory();
virtual ~SDLFactory();
...
Enemy* createEnemy(int,int,int,int,int,int,int,int);
...
HealthPowerUp* createHealthPowerUp(int,int,int);
SpeedPowerUp* createSpeedPowerUp(int,int,int);
...
};

sdlfactory.cpp(部分代码)

Enemy* SDLFactory::createEnemy(int x,int y,int maxHealth,int maxSpeed,int acceleration,int brakeSpeed,int damage,int bulletSpeed)
{
Waepon* loadedWaepon=createWaepon(x,y,damage,bulletSpeed);
return new SDLEnemy(x,y,maxHealth,maxSpeed,acceleration,brakeSpeed,loadedWaepon,this);
}
HealthPowerUp* SDLFactory::createHealthPowerUp(int x,int y,int effect){
return new SDLHealthPowerUp(x,y,effect,this);
}
SpeedPowerUp* SDLFactory::createSpeedPowerUp(int x,int y,int effect){
return new SDLSpeedPowerUp(x,y,effect,this);
}

gamelogics .h(一些代码)

class GameLogic 
{
protected:
AbstractFactory* factory;
public:
GameLogic(AbstractFactory*);
virtual ~GameLogic();
void createLevel(container&, int);

};

gamelogic.cpp(部分代码)

void GameLogic::createLevel(container& entities,const int level){
srand(time(NULL));
//create enemies
int x=0;
int spawnRate=1000-25*level;
while((x+=rand()%(spawnRate))<MAXHEIGHT){
    int y=rand()%MAXRIGHT;
    int maxHealth=rand()%(100+10*level);
    int speed=50+rand()%75;
    int acceleration=5+rand()%10;
    int brakeSpeed=10+rand()%15;
    int damage=25+rand()%(15*level);
    int waeponspeed=150+rand()%(150);
    entities.push_back(factory->createEnemy(x,y,maxHealth,speed,acceleration,brakeSpeed,damage,waeponspeed));
}
x=0;
while((x+=rand()%spawnRate)<MAXHEIGHT){
    int y=rand()%MAXRIGHT;
    int effect=50+rand()%50;
//the following line of code gives me a compile error
    entities.push_back(factory->createSpeedPowerUp(x,y,effect));
}
x=0;
while((x+=rand()%spawnRate)<MAXHEIGHT){
    int y=rand()%MAXRIGHT;
    int effect=50+rand()%50;
    entities.push_back(factory->createHealthPowerUp(x,y,effect));
}

}

编译错误:

../GameLogic.cpp: In member function 'void CDS::GameLogic::createLevel(CDS::container&, int)':
../GameLogic.cpp:39: error: no matching function for call to 'std::vector<CDS::Entitie*, std::allocator<CDS::Entitie*> >::push_back(CDS::SpeedPowerUp*)'
/usr/include/c++/4.0.0/bits/stl_vector.h:602: note: candidates are: void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = CDS::Entitie*, _Alloc = std::allocator<CDS::Entitie*>]
make: *** [GameLogic.o] Error 1

您正在尝试将SpeedPowerUp添加到Entitie的向量中。您可能想要确保您的SpeedPowerUp实际上继承自Entitie。

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