设计模式(1)---简单工厂模式

 1 #include <memory>
 2 #include <string>
 3 #include <iostream>
 4 
 5 using namespace std;
 6 
 7 class Operation
 8 {
 9 public:
10     Operation(double numberA = 0, double numberB = 0) :numberA_(numberA), numberB_(numberB)
11     {}
12     void setNumberA(double numberA)
13     {
14         numberA_ = numberA;
15     }
16     double getNumberA(void)
17     {
18         return numberA_;
19     }
20     void setNumberB(double numberB)
21     {
22         numberB_ = numberB;
23     }
24     double getNumberB(void)
25     {
26         return numberB_;
27     }
28     virtual double getResult(void) = 0;
29 protected:
30     double numberA_;
31     double numberB_;
32 };
33 
34 class OperationAdd : public Operation
35 {
36 public:
37     double getResult(void)
38     {
39         return numberA_ + numberB_;
40     }
41 };
42 
43 class OperationSub : public Operation
44 {
45 public:
46     double getResult(void)
47     {
48         return numberA_ - numberB_;
49     }
50 };
51 
52 shared_ptr<Operation> createOperationFactory(char operate)
53 {
54     switch (operate)
55     {
56     case ‘+‘:
57         return make_shared<OperationAdd>();
58     case ‘-‘:
59         return make_shared<OperationSub>();
60     default:
61         cout << "can not distinguish the operate:" << operate << endl;
62         return nullptr;
63     }
64 }
65 
66 int main()
67 {
68     shared_ptr<Operation> operateAdd = createOperationFactory(‘+‘);
69     if (nullptr == operateAdd)
70     {
71         return -1;
72     }
73     operateAdd->setNumberA(20.00);
74     operateAdd->setNumberB(30.00);
75 
76     cout << operateAdd->getNumberA() << " + " << operateAdd->getNumberB() << " = " << operateAdd->getResult() << endl;
77     return 0;
78 }
79