标签：Gumin name Observer 11.21 public observers void
实验 21：观察者模式
本次实验属于模仿型实验，通过本次实验学生将掌握以下内容：
1、理解观察者模式的动机，掌握该模式的结构；
2、能够利用观察者模式解决实际问题。
[实验任务一]：股票提醒
当股票的价格上涨或下降5%时，会通知持有该股票的股民，当股民听到价格上涨的消息时会买股票，当价格下降时会大哭一场。
实验要求：
1. 画出对应类图；
2. 提交源代码；
package test21;
import java.util.ArrayList;
public class Gufen extends Subject{
public void up(){
System.out.println("****股份上涨15%****");
for(Observer guan:observers){
guan.buy();
}
}
public void down(){
System.out.println("****股份下跌15%****");
for(Observer guan:observers){
guan.cry();
}
}
}
package test21;
public class Gumin implements Observer{
private String name;
public Gumin(String a){name=a;}
public void buy(){
System.out.println("股民"+name+"买了一些股票");
}
public void cry(){
System.out.println("股民"+name+"哭了");
}
}
package test21;
public class main {
public static void main(String[] args) {
Gufen f=new Gufen();
Gumin g1=new Gumin("小张");
Gumin g2=new Gumin("小龚");
f.attach(g1);
f.attach(g2);
f.up();
f.down();
}
}
package test21;
public interface Observer {
public void buy();
public void cry();
}
package test21;
import java.util.ArrayList;
public abstract class Subject {
protected ArrayList<Observer> observers;
public Subject(){
observers=new ArrayList<>();
}
public void attach(Observer a){
observers.add(a);
}
public void detach(Observer a){
observers.remove(a);
}
public abstract void up();
public abstract void down();
}
#include<iostream>
#include<list>
#include<string>
using namespace std;
//抽象观察者
class Observer{
protected:
string name;
public:
virtual void buy()=0;
virtual void cry()=0;
};
//具体观察者
class Gumin:public Observer{
public:
Gumin(string name){
this->name=name;
}
void buy(){
cout<<"股民"<<name<<"买了一些股票"<<endl;
}
void cry(){
cout<<"股民"<<name<<"哭了"<<endl;
}
};
//抽象主题类
class Subject{
protected:
list<Observer*> observers;
public:
void attach(Observer *obs){
observers.push_back(obs);
}
void detach(Observer *obs){
observers.remove(obs);
}
virtual void up()=0;
virtual void down()=0;
};
//具体主题类
class Gufen:public Subject{
public:
void up(){
cout<<"*****股份上涨15%*****"<<endl;
list<Observer*>::iterator iter = observers.begin();
for(; iter != observers.end(); iter++)
(*iter)->buy();
}
void down(){
cout<<"*****股份下跌15%*****"<<endl;
list<Observer*>::iterator iter = observers.begin();
for(; iter != observers.end(); iter++)
(*iter)->cry();
}
};
//测试函数
int main(){
Observer *obs1,*obs2;
obs1=new Gumin("小张");
obs2=new Gumin("小龚");
Subject *sub;
sub=new Gufen();
sub->attach(obs1);
sub->attach(obs2);
sub->up();
sub->down();
}
标签：Gumin,
name,
Observer,
11.21,
public,
observers,
void
From： https://www.cnblogs.com/0608lin/p/18560711