C++深层复制解决指针悬挂

 1 #include <iostream>
 2 #include <cstring>
 3 
 4 using namespace std;
 5 
 6 class mystring{
 7     public:
 8         mystring(string s){
 9             cout<<"Constructor called."<<endl;
10             ptr = new char[s.length()+1];
11             strcpy(ptr,s.c_str());
12         }
13         ~mystring(){
14             cout<<"Destructor called.---"<<ptr<<endl;
15             delete ptr;
16         }
17         mystring &operator=(const mystring&);
18     private:
19         char* ptr;
20 };
21 
22 mystring& mystring::operator=(const mystring& s){
23     if(this == &s) return *this;
24     cout<<this<<" "<<sizeof(this)<<endl;
25     delete ptr;
26     ptr = new char[strlen(s.ptr)+1];
27     strcpy(ptr,s.ptr);
28     return *this;
29 }
30 
31 int main(){
32     mystring p1("hello");
33     mystring p2("OK");
34     p1 = p2;
35 
36     return 0;
37 }