赋值和初始化

 1 #include <iostream>
 2 using std::cout; using std::cin; using std::endl;
 3 #include "HasPtr.h"
 4 
 5 int main()
 6 {
 7     HasPtr ha("Halo");
 8     cout<<ha.getPs()<<endl;
 9     HasPtr copy_ha(ha);
10     cout<<copy_ha.getPs()<<endl;
11     HasPtr assign_ha;
12     //HasPtr assign_ha = ha;
13     assign_ha = ha;
14     cout<<assign_ha.getPs()<<endl;
15     return 0;
16 }

 1 //HasPtr.h
 2 #ifndef HASPTR_H
 3 #define HASPTR_H
 4 
 5 #include <iostream>
 6 #include <string>
 7 
 8 class HasPtr
 9 {
10     public:
11         HasPtr(const std::string& s = std::string()) : ps(new std::string(s)), i(0) { }
12         HasPtr(const HasPtr&);
13         std::string* getPs() const { return ps; } //由于原本就不可以对私有成员进行操作，所以不必返回引用
14         int getI() const { return i; }
15         HasPtr& operator=(const HasPtr&);
16         ~HasPtr();
17     private:
18         std::string *ps;
19         int i;
20 };
21 
22 #endif // HASPTR_H

 1 //HasPtr.cpp
 2 #include "HasPtr.h"
 3 
 4 HasPtr::HasPtr(const HasPtr& h)
 5 {
 6     ps = new std::string(*(h.ps));
 7     i = h.i;
 8     std::cout<<"call the copyCtor."<<std::endl;
 9 }
10 
11 HasPtr::~HasPtr()
12 {
13     std::cout<<"call the dtor."<<std::endl;
14     delete ps;
15 }
16 
17 HasPtr& HasPtr::operator= (const HasPtr& rhs)
18 {
19     std::cout<<"call the assignment operator."<<std::endl;
20     ps = new std::string(*(rhs.ps));
21     i = rhs.i;
22     return *this;
23 }