String类简单了解

 

 

 1 #include <stdio.h>
 2 #include <string.h>
 3 
 4 class String
 5 {
 6 public:
 7     String(const char *str = NULL);
 8     ~String();
 9     String(const String &other);
10     String& operator = (const String &other);
11 private:
12     char *m_data;
13 };
14 
15 String::~String()
16 {
17     delete [] m_data;
18 }
19 
20 String::String(const char *str)
21 {
22     if (!str) 
23     {
24         m_data = new char[1];
25         m_data[0] = '\0';
26     }
27     else
28     {
29         int len = strlen(str);
30         m_data = new char[len + 1];
31         strcpy(m_data, str);
32     }
33 }
34 
35 String::String(const String& other)
36 {
37     /*
38     if (!other) 
39     {
40         m_data = new char[1];
41         m_data = '\0';
42     }
43     else
44     {
45 */
46         delete m_data;
47         int len = strlen(other.m_data);
48         m_data = new char[len + 1];
49         strcpy(m_data, other.m_data);
50 
51     //}
52 }
53 
54 String & String::operator=(const String& other)
55 {
56     if (this == &other) 
57     {
58         return *this;
59     }
60     else
61     {
62         delete m_data;
63         int len = strlen(other.m_data);
64         m_data = new char[len + 1];
65         strcpy(m_data, other.m_data);
66         return *this;
67     }
68 }
69 
70 
71 int main()
72 {
73 
74     return 0;
75 }

 

转载于:https://www.cnblogs.com/Clin/archive/2011/11/09/2242221.html