1 #define _CRT_SECURE_NO_WARNINGS
2 #include <iostream>
3 #include <locale.h>
4 using namespace std;
5
6 //返回值为类的引用不会调用拷贝构造
7 //拷贝构造要深拷贝,赋值重载(=)也要深拷贝
8 //注意对象如果是在栈上,有生命周期,拷贝栈上的对象需要深拷贝
9
10 class mystring
11 {
12 public:
13 char *p;
14 int n;
15
16 public:
17 mystring() : p(nullptr), n(0)
18 {
19
20 }
21 mystring(char *str)
22 {
23 p = new char[strlen(str) + 1];
24 n = strlen(str) + 1;
25 strcpy(p, str);
26 }
27
28 mystring(const mystring &my)
29 {
30 n = my.n;
31 p = new char[n];
32 strcpy(p, my.p);
33 }
34
35 ~mystring()
36 {
37 delete p;
38 }
39
40 //void operator +(mystring &str)
41 //{
42 // this->n += strlen(str.p);
43 // //分配内存
44 // char *ptemp = new char[this->n];
45 // //拷贝
46 // strcpy(ptemp, this->p);
47 // strcat(ptemp, str.p);
48 // delete this->p;
49 // this->p = ptemp;
50 //}
51
52 //返回一个对象
53 //mystring operator +(mystring &str)
54 //{
55 // this->n += strlen(str.p);
56 // //分配内存
57 // char *ptemp = new char[this->n];
58 // //拷贝
59 // strcpy(ptemp, this->p);
60 // strcat(ptemp, str.p);
61 // delete this->p;
62 // this->p = ptemp;
63
64 // return (*this);
65 //}
66
67 //如果返回的是引用则不会调用拷贝构造
68 mystring &operator +(mystring &str)
69 {
70 this->n += strlen(str.p);
71 //分配内存
72 char *ptemp = new char[this->n];
73 //拷贝
74 strcpy(ptemp, this->p);
75 strcat(ptemp, str.p);
76 delete this->p;
77 this->p = ptemp;
78
79 return (*this);
80 }
81 };
82
83 void main()
84 {
85 mystring *my1 = new mystring("hello");
86 mystring *my2 = new mystring("world");
87 mystring my3 = *my1 + *my2;
88 delete my1;
89 cout << my3.p << endl;
90 cin.get();
91 }
