- 默认构造，析构
- 拷贝构造，移动构造
- 拷贝赋值，移动赋值
- 取值
- 右值引用
- 其它
- 基类的析构函数应使用virtual 关键字，保证子类的析构函数能够被正常调用
- 作为接口类，如果不是基类，应该用final关键字
1 // g++ testClass.cc -g -std=c++11 && ./a.out
2 #include <iostream>
3 #include <string.h>
4 using namespace std;
5
6 class MyStr final
7 {
8 private:
9 char *name = NULL;
10 int id;
11 inline void MyStrncpy(char *dst, const char *src, size_t len) {
12 if (dst != src) {
13 strncpy(dst, src, len);
14 dst[len] = '\0';
15 }
16 }
17 inline void Reset() {
18 id = 0;
19 if (name) {
20 delete[] name;
21 name = NULL;
22 }
23 }
24 inline void Clear() {
25 id = 0;
26 name = NULL;
27 }
28 inline void DeepCopy(const MyStr &other) {
29 id = other.id;
30 name = new char[strlen(other.name) + 1];
31 MyStrncpy(name, other.name, strlen(other.name));
32 }
33 inline void ShallowCopy(const MyStr &other) {
34 id = other.id;
35 name = other.name;
36 }
37 public:
38 // 默认构造函数
39 explicit MyStr():id(0),name(NULL) {
40 cout << "构造: " << __func__ << endl;
41 }
42 // 构造函数
43 explicit MyStr(int _id, char *_name) {
44 cout << "普通构造： " << __func__ << endl;
45 id = _id;
46 name = new char[strlen(_name) + 1];
47 MyStrncpy(name, _name, strlen(_name));
48 }
49 // 析构函数
50 ~MyStr() {
51 cout << "析构： " << __func__ << endl;
52 Reset();
53 }
54 // 拷贝构造
55 MyStr(const MyStr& other) {
56 cout << "拷贝构造： " << __func__ << endl;
57 DeepCopy(other);
58 }
59 // 移动构造
60 MyStr(MyStr &&other) {
61 cout << "移动构造： " << __func__ << endl;
62 ShallowCopy(other);
63 other.Clear();
64 }
65 // 拷贝赋值， rhs means right hand side value
66 MyStr &operator=(const MyStr &rhs) {
67 cout << "拷贝赋值： " << __func__ << endl;
68 if (this != &rhs) {
69 Reset();
70 DeepCopy(rhs);
71 }
72 return *this;
73 }
74 // 移动赋值
75 MyStr &operator=(MyStr &&rhs) {
76 cout << "移动赋值： " << __func__ << endl;
77 if (this != &rhs) {
78 Reset();
79 ShallowCopy(rhs);
80 rhs.Clear();
81 }
82 return *this;
83 }
84 };
85
86 int main()
87 {
88 cout << "普通构造====================" << endl;
89 MyStr str1(1, (char*)"aaa");
90 cout << "普通构造====================" << endl;
91 MyStr str2(2, (char*)"bbbb");
92 cout << "拷贝赋值====================" << endl;
93 str2 = str1;
94 cout << "拷贝构造====================" << endl;
95 MyStr str3 = str2;
96 cout << "拷贝构造====================" << endl;
97 MyStr str4(str2);
98 cout << "移动构造====================" << endl;
99 MyStr str5(std::move(str2));
100 cout << "移动构造====================" << endl;
101 MyStr str6 = std::move(str5);
102 cout << "普通构造====================" << endl;
103 MyStr str7(3, (char*)"ccccc");
104 cout << "移动赋值====================" << endl;
105 str7 = std::move(str6);
106 return 0;
107 }
