來自于《大話設計模式》
模板方法模式：定義一個操作中的算法的骨架，而將一些步驟延遲到子類中。模板方法使得子類可以不改變一個算法的結構即可重定義該算法的某些特定步驟。
盡量將公共操作上移到基類中，這樣便于修改，代碼復用性更強。
UML 類圖：
代碼實現 C++：
1 #include <iostream>
2 #include <string>
3 using namespace std;
4
5 class TestPaper
6 {
7 public:
8 virtual void TestQuestion1()
9 {
10 cout << "TestQuestion1" << endl;
11 cout << "Answer: " << Answer1() << endl;
12 }
13 virtual void TestQuestion2()
14 {
15 cout << "TestQuestion2" << endl;
16 cout << "Answer: " << Answer2() << endl;
17 }
18 virtual void TestQuestion3()
19 {
20 cout << "TestQuestion3" << endl;
21 cout << "answer: " << Answer3() << endl;
22 }
23 virtual const string Answer1() = 0
24 {
25 return "";
26 }
27 virtual const string Answer2() = 0
28 {
29 return "";
30 }
31 virtual const string Answer3() = 0
32 {
33 return "";
34 }
35 };
36
37 class TestPaperA : public TestPaper
38 {
39 public:
40 virtual const string Answer1()
41 {
42 return "a";
43 }
44 virtual const string Answer2()
45 {
46 return "b";
47 }
48 virtual const string Answer3()
49 {
50 return "c";
51 }
52 };
53
54 class TestPaperB : public TestPaper
55 {
56 public:
57 virtual const string Answer1()
58 {
59 return "c";
60 }
61 virtual const string Answer2()
62 {
63 return "b";
64 }
65 virtual const string Answer3()
66 {
67 return "a";
68 }
69 };
70
71 int main()
72 {
73 TestPaperA a;
74 a.TestQuestion1();
75 a.TestQuestion2();
76 a.TestQuestion3();
77
78 TestPaperB b;
79 b.TestQuestion1();
80 b.TestQuestion2();
81 b.TestQuestion3();
82
83 TestPaper* p;
84 p = new TestPaperA;
85 p->TestQuestion1();
86 p->TestQuestion2();
87 p->TestQuestion3();
88 delete p;
89
90 p = new TestPaperB;
91 p->TestQuestion1();
92 p->TestQuestion2();
93 p->TestQuestion3();
94 delete p;
95
96 return 0;
97 }
posted on 2011-04-25 16:41
unixfy 閱讀(170)
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