1 class mystring
2 {
3 private:
4 char *s;
5 static mystring *self;
6 public:
7 ~ mystring();
8 const char *get_s() const;
9 const void set_s(const char *s);
10 static mystring *makestring(const char *s = NULL);
11 static void deletestring();
12 protected:
13 mystring();
14 mystring(const mystring &it); //构造函数
15 mystring(const char *s);
16
17 };
18
19 mystring *mystring::self = NULL;
20
21 mystring::mystring():s(NULL)
22 {
23
24 }
25
26 mystring::mystring(const char *s)
27 {
28 int len = strlen(s);
29 this->s = new char[len +1];
30 strcpy(this->s,s);
31 this->s[len] = 0;
32 }
33
34
35 mystring::mystring(const mystring &it) //通过拷贝构造函数实现深拷贝
36 {
37 int len = strlen(it.get_s());
38 this->s = new char[len +1];
39 strcpy(this->s, it.s);
40 this->s[len] = 0;
41 }
42
43 mystring::~mystring()
44 {
45 delete s;
46 s = NULL;
47 }
48
49 const char *mystring::get_s() const
50 {
51 return s;
52 }
53
54 const void mystring::set_s(const char *s)
55 {
56 if(this->s == NULL)
57 {
58 int len = strlen(s);
59 this->s = new char[len +1];
60 strcpy(this->s, s);
61 this->s[len] = 0;
62 }
63 else
64 {
65 int len1 = strlen(this->s);
66 int len2 = strlen(s);
67 if(len1 >= len2)
68 {
69 strcpy(this->s, s);
70 this->s[len2] = 0;
71 }
72 else
73 {
74 delete []this->s;
75 this->s = new char[len2+1];
76 strcpy(this->s, s);
77 this->s[len2] = 0;
78 }
79 }
80 }
81
82 mystring *mystring::makestring(const char *s)
83 {
84 if(self == NULL)
85 {
86 if(s == NULL)
87 {
88 self = new mystring;
89 }
90 else
91 {
92 self = new mystring(s);
93 }
94 }
95 return self;
96 }
97
98 void mystring::deletestring()
99 {
100 if(self != NULL)
101 {
102 delete self;
103 self = NULL;
104 }
105
106 }
