防御塔攻击小兵，C++观察者模式

#include 
#include 
#include 
using namespace std;

//通知者抽象类
class Subject;

//观察者抽象类
class Observer {
public:
    Observer(string name, Subject* sub) {
        this->name = name;
        this->sub = sub;
    }
    virtual void update() = 0;
protected:
    string name;
    Subject* sub;
};

//通知者抽象类
class Subject {
public:
    string action;
    virtual void attach(Observer*) = 0;
    virtual void detach(Observer*) = 0;
    virtual void notify() = 0;
protected:
    list observers; //观察者列表
};



//具体观察者
class Tower: public Observer {
public:
    Tower(string name, Subject* sub) : Observer(name, sub) {
        
    }
    void update() {
        cout << name << "收到消息：" << sub->action << endl;
        if (sub->action == "小兵进塔了") {
            cout << name << ": 攻击小兵" << endl;
        }
    }
};

//具体通知者
class Soldier: public Subject {
public:
    void attach(Observer* obs) {
        observers.push_back(obs);
    }
    void detach(Observer* obs) {
        observers.remove(obs);
    }
    void notify() {
        for (auto it : observers) {
            it->update();
        }
    }
};

int main() {
    
    //小兵是一个通知者
    Subject* soldier = new Soldier();
    
    //被观察的对象
    Observer* A_tower1 = new Tower("防御塔A1", soldier);
    Observer* A_tower2 = new Tower("防御塔A2", soldier);
    Observer* B_tower = new Tower("防御塔B", soldier);
    
    //把三个塔添加到观察队列中
    soldier->attach(A_tower1);
    soldier->attach(A_tower2);
    soldier->attach(B_tower);
    
    //小兵发起行动，并通知各位观察者
    soldier->action = "小兵进塔了";
    soldier->notify();
    cout << endl;
    
    //小兵发起行动，并通知各位观察者
    soldier->action = "小兵没进塔";
    soldier->notify();
    cout << endl;
    
    //把A1塔移出观察者队列，小兵发起行动，并通知各位观察者
    soldier->detach(A_tower1 );
    soldier->action = "小兵进塔了";
    soldier->notify();
    
    return 0;
}

结果：