{

public:

virtual ~Spawner() {}

virtual Monster* spawnMonster() = 0;

{

public:

virtual Monster* spawnMonster()

{

return new Ghost();

}

{

public:

virtual Monster* spawnMonster()

{

return new Demon();

}

{

public:

virtual ~Monster() {}

virtual Monster* clone() = 0;

// 其他代码……

public:

Ghost(int health, int speed)

: health_(health),

speed_(speed)

{}

virtual Monster* clone()

{

return new Ghost(health_, speed_);

}

private:

int health_;

int speed_;

{

public:

Spawner(Monster* prototype)

: prototype_(prototype)

{}

Monster* spawnMonster()

{

return prototype_->clone();

}

private:

Monster* prototype_;

{

//^spawn-ghost-clone

Monster* ghostPrototype = new Ghost(15, 3);

Spawner* ghostSpawner = new Spawner(ghostPrototype);

//^spawn-ghost-clone

use(ghostSpawner);

{

public:

Spawner(SpawnCallback spawn)

: spawn_(spawn)

{}

Monster* spawnMonster()

{

return spawn_();

}

private:

SpawnCallback spawn_;

{

//^spawn-ghost-callback

Spawner* ghostSpawner = new Spawner(spawnGhost);

//^spawn-ghost-callback

use(ghostSpawner);

{

public:

virtual ~Spawner() {}

virtual Monster* spawnMonster() = 0;

{

public:

virtual Monster* spawnMonster() { return new T(); }

{

//^use-templates

Spawner* ghostSpawner = new SpawnerFor<Ghost>();

//^use-templates

use(ghostSpawner);