設計模式——策略模式（C++實現）

程式優化是用於消除程式中大量的if else這種判斷語句

 1 #include <iostream>
 2 #include <string>
 3 
 4 using namespace std;
 5 
 6 class CashSuper
 7 {
 8 public:
 9         virtual double GetTotalCash(double ddwMoney) = 0;
10 };
11 
12 class CashNormal:public CashSuper
13 {
14 public:
15         virtual double GetTotalCash(double ddwMoney)
16         {
17                 return ddwMoney;
18         }
19 };
20 
21 class CashRebate: public CashSuper
22 {
23 public:
24         CashRebate(float dwRebate):m_Rebate(dwRebate)
25         {
26 
27         }
28 
29         virtual double GetTotalCash(double ddwMoney)
30         {
31                 return m_Rebate * ddwMoney;
32         }
33 
34 private:
35         float m_Rebate;
36 };
37 
38 class CashContext
39 {
40 public:
41         CashContext()
42         {
43         }
44 
45         CashContext(CashSuper* pstTmpCashSuper)
46         {
47                 m_pstCashSuper = pstTmpCashSuper;
48         }
49 
50         void SetCashStrategy(CashSuper* pstTmpCashSuper)
51         {
52                 m_pstCashSuper = pstTmpCashSuper;
53         }
54 
55         double GetTotalCash(double ddwMoney)
56         {
57                 return m_pstCashSuper->GetTotalCash(ddwMoney);
58         }
59 
60 private:
61         CashSuper *m_pstCashSuper;
62 };
63 
64 int main(void)
65 {
66         CashContext* stCashContext = new CashContext(new CashNormal());
67 
68         cout<<"應付價錢為： "<< stCashContext->GetTotalCash(100)<< endl;
69 
70         stCashContext = new CashContext(new CashRebate(0.8));
71 
72         cout<<"應付價錢為： "<< stCashContext->GetTotalCash(100)<< endl;
73 
74         return 0;
75 }
76 ///////
77 [root]$ ./strategy       
78 應付價錢為： 100
79 應付價錢為： 80