來自于《大話設計模式》
原型模式（Prototype）：用原型實例指定創建對象的種類，并且通過拷貝這些原型創建新的對象。
這個設計模式在 C++ 中如何實現？
UML 圖：
代碼實現 C++：
1 #include <iostream>
2 using namespace std;
3
4 class Prototype
5 {
6 public:
7 virtual Prototype& Clone() = 0;
8 };
9
10 class ConcretePrototype
11 {
12 private:
13 int m;
14 char* str;
15 public:
16 ConcretePrototype(int n = 0, const char* s = "") : m(n)
17 {
18 str = new char[strlen(s) + 1];
19 if (str == 0)
20 {
21 exit(1);
22 }
23 strcpy(str, s);
24 }
25 ConcretePrototype(const ConcretePrototype& p)
26 {
27 str = new char[strlen(p.str) + 1];
28 if (str == 0)
29 {
30 exit(1);
31 }
32 strcpy(str, p.str);
33 m = p.m;
34 }
35 ConcretePrototype& operator =(const ConcretePrototype& p)
36 {
37 if (this == &p)
38 {
39 delete [] str;
40 str = new char[strlen(p.str) + 1];
41 if (str == 0)
42 {
43 exit(1);
44 }
45 strcpy(str, p.str);
46 m = p.m;
47 }
48 return *this;
49 }
50 ~ConcretePrototype()
51 {
52 delete [] str;
53 }
54 ConcretePrototype& Clone()
55 {
56 return *this;
57 }
58 void SetStr(const char* s = "")
59 {
60 delete [] str;
61 str = new char[strlen(s) + 1];
62 if (str == 0)
63 {
64 exit(1);
65 }
66 strcpy(str, s);
67 }
68 void SetM(int n)
69 {
70 m = n;
71 }
72 void SetStrAndM(const char* s, int n)
73 {
74 delete [] str;
75 str = new char[strlen(s) + 1];
76 if (str == 0)
77 {
78 exit(1);
79 }
80 strcpy(str, s);
81 m = n;
82 }
83 void test()
84 {
85 cout << m << endl;
86 cout << str << endl;
87 }
88 };
89
90 int main()
91 {
92 ConcretePrototype c(5, "abc");
93 c.test();
94
95 ConcretePrototype c2 = static_cast<ConcretePrototype>(c.Clone());
96 c2.test();
97
98 c2.SetStrAndM("xyz", 7);
99 c2.test();
100
101 return 0;
102
103 }
posted on 2011-04-25 16:03
unixfy 閱讀(300)
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