策略模式

  1 #include<iostream>
  2 #include<string>
  3 #include<memory>
  4 using namespace std;
  5 
  6 //strategy抽象类，用作接口
  7 class Strategy
  8 {
  9 public:
 10     virtual double GetResult(double money) = 0;
 11     virtual ~Strategy()
 12     {
 13         cout<<" in the destructor of Strategy"<<endl;
 14     }
 15 };
 16 //正常结算方式
 17 class CashNormal : public Strategy
 18 {
 19     double GetResult(double money)
 20     {
 21         return money;
 22     }
 23     ~CashNormal()
 24     {
 25         cout<<" in the destructor of CashNormal"<<endl;
 26     }
 27 };    
 28 //打折
 29 class CashRebate : public Strategy
 30 {
 31 private:
 32     double moneyRebate;  //折扣率
 33 public:
 34     //构造函数
 35     CashRebate(double rebate)
 36     {
 37         moneyRebate = rebate;
 38     }
 39 
 40     double GetRebate()
 41     {
 42         return moneyRebate;
 43     }
 44     void SetRebate(double rebate)
 45     {
 46         moneyRebate = rebate;
 47     }
 48 
 49     double GetResult(double money)
 50     {
 51         return money * moneyRebate;
 52     }
 53 };
 54 //返现
 55 class CashReturn : public Strategy
 56 {
 57     //返现的条件与方式
 58 private:
 59     double moneyCondition;
 60     double moneyReturn;
 61 public:
 62     //构造函数
 63     CashReturn(double condition, double re)
 64     {
 65         moneyCondition = condition;
 66         moneyReturn = re;
 67     }
 68 
 69     double GetCondition()
 70     {
 71         return moneyCondition;
 72     }
 73     void SetCondition(double condition)
 74     {
 75         moneyCondition = condition;
 76     }
 77     double GetReturn()
 78     {
 79         return moneyReturn;
 80     }
 81     void SetReturn(double re)
 82     {
 83         moneyReturn = re; 
 84     }
 85 
 86     double GetResult(double money)
 87     {
 88         if(money >= moneyCondition)
 89         {
 90             money = money - (int)(money / moneyCondition) * moneyReturn;
 91         }
 92         return money;
 93     }
 94 };
 95 
 96 //现金收费工厂类
 97 class CashFactory
 98 {
 99 public:
100     static Strategy* createGetResult(int type)
101     {
102         Strategy* cs;
103         switch(type)
104         {
105         case 0:
106             cs = new CashNormal();
107             break;
108         case 1:
109             cs = new CashRebate(0.8);
110             break;
111         case 2:
112             cs = new CashReturn(300,100);
113             break;
114         default:
115             break;
116         }
117         return cs;
118     }
119 };
120 
121 //CashContext类   策略模式与简单工厂模式相结合
122 class CashContext
123 {
124 private:
125     Strategy* cs;
126 public:
127     CashContext(int type)
128     {
129         bool loop = true;
130         while(loop){
131         switch (type)
132         {
133         case 0:
134             cs =new CashNormal();
135             loop = false;
136             break;
137         case 1:
138             cs = new CashRebate(0.8);
139             loop = false;
140             break;
141         case 2:
142             cs = new CashReturn(300,100);
143             loop = false;
144             break;
145         default:
146             cout<<"输入有误! 请重新输入!"<<endl;
147             cin>>type;
148             break;
149         }
150         }
151     }
152 
153     double GetResult(double money)
154     {
155         return cs->GetResult(money);
156     }
157 };

 1 #include "Strategy.h"
 2 void main(int argc, char *argv)
 3 {
 4     int type = 0;
 5     double total = 0;
 6     cout<<"选择收费方式:"<<endl
 7         <<"0:正常方式"<<endl
 8         <<"1:打折方式"<<endl
 9         <<"2:返现方式"<<endl;
10     cin >> type;
11     /*
12     CashFactory cfactory;
13     Strategy *pay = cfactory.createGetResult(type);
14     cout<<"输入总的消费金额:";
15     cin >> total;
16     cout<<"应收金额为:"<<pay->GetResult(total)<<endl;
17     */
18     CashContext cs(type);
19     cout<<"输入总的消费金额:";
20     cin >> total;
21     cout<<"应收金额为:"<<cs.GetResult(total)<<endl;
22 }