设计模式（一）：简单工厂模式

 1 #include<iostream>
 2 #include<string.h>
 3 #include<stdio.h>
 4 #include<stdlib.h>
 5 using namespace std;
 6 /*
 7 设计模式（一）：简单工厂模式
 8 优点：适用于不同情况创建不同的类时；
 9 缺点：客户端必须要知道基类和工厂类，耦合性差
10 */
11 
12 //产品类-基类
13 class COperation
14 {
15 public:
16     int m_nFirst;
17     int m_nSecond;
18     virtual double GetResult()
19     {
20         double dResult = 0;
21         return dResult;
22     }
23 };
24 
25 //生成派生类-加法，也就是产品A
26 class AddOperation :public COperation
27 {
28 public:
29     virtual double GetResult()
30     {
31         return m_nFirst + m_nSecond;
32     }
33 };
34 
35 //生成派生类-减法，也就是产品B
36 class SubOperation :public COperation
37 {
38 public:
39     virtual double GetResult()
40     {
41         return m_nFirst - m_nSecond;
42     }
43 };
44 
45 //工厂类
46 class CCalculatorFactory
47 {
48 public:
49     static COperation* Create(char cOperator);
50 };
51 
52 COperation*  CCalculatorFactory::Create(char cOperator)
53 {
54     COperation* oper;
55     switch (cOperator)
56     {
57     case ‘+‘:
58         oper = new AddOperation();
59         break;
60     case ‘-‘:
61         oper = new SubOperation();
62         break;
63     default:
64         oper = new AddOperation();
65         break;
66     }
67     return oper;
68 }
69 
70 int main(int argc,char** argv)
71 {
72     int a, b;
73     cin >> a >> b;
74     COperation* oper = CCalculatorFactory::Create(‘+‘);
75     oper->m_nFirst = a;
76     oper->m_nSecond = b;
77     cout << oper->GetResult();
78     system("pause");
79     return 0;
80 }