85.深浅拷贝

 1 #define _CRT_SECURE_NO_WARNINGS
 2 #include <iostream>
 3 #include <cstring>
 4 using namespace std;
 5 
 6 //默认拷贝构造只是值传递,对于数据有效,对于指针则是同一个指向,需要重写一下拷贝构造
 7 //类的内部有指针分配内存,需要深拷贝,否则需要浅拷贝
 8 class mystring
 9 {
10 public:
11     char *pstr;
12     int length;
13 
14 public:
15     mystring(char *str)
16     {
17         this->length = strlen(str) + 1;
18         this->pstr = new char[this->length]{ 0 };
19         strcpy(this->pstr, str);//初始化
20     }
21 
22     //拷贝构造
23     mystring(const mystring &mystr)
24     {
25         this->length = mystr.length;
26         this->pstr = new char[this->length]{ 0 };
27         strcpy(this->pstr, mystr.pstr);
28     }
29 
30 
31     void show()
32     {
33         cout << length << " " << (void *)pstr << "  " << endl;
34     }
35 };
36 
37 
38 void main()
39 {
40     mystring str1("gogogo");
41     str1.show();
42     //浅拷贝指向的地址都一样
43     mystring str2(str1);
44     str2.show();
45     cin.get();
46 }