C++类中的继承实例详解

#include<iostream> 
#include<string> 
using namespace std; 
 
 
 
class Person 
{ 
public: 
 Person(const char* name = "abc") 
  :_name(name) 
 { 
  cout << "Person()" << endl; 
 } 
 
 Person(const Person& pp) 
  :_name(pp._name) 
 { 
  cout << "Person(const Person&)" << endl; 
 } 
 
 
 Person& operator=(const Person& pp) 
 { 
  cout << "Person& operator=(const Person&)" << endl; 
  if (this != &pp) 
  { 
   _name = pp._name; 
  } 
  return *this; 
 } 
 
 ~Person() 
 { 
  cout << "~Person()" << endl; 
 } 
 
protected: 
 string _name; 
}; 
 
 
 
class Student :public Person 
{ 
public: 
 Student(const char* name,int num) 
  :Person(name),_num(num) 
 { 
  cout << "Student()" << endl; 
 } 
 
 Student(const Student& A) 
  :Person(A),_num(A._num) 
 { 
  cout << "Student(const Student& A)" << endl; 
 } 
 
 Student& operator=(const Student& A) 
 { 
  cout << "Student& operator=(const Student& A)" << endl; 
  if (this != &A) 
  { 
   Person::operator=(A); 
   _num = A._num; 
  } 
  return *this; 
 } 
 
 ~Student() 
 { 
  cout << "~Student()" << endl; 
 } 
 
 
 
private: 
 int _num; 
}; 
 
 
void test() 
{ 
 
 Student a1("peter",20); 
 Student a2(a1); 
 a2 = a1; 
} 
 
 
 
int main() 
{ 
 test(); 
 return 0; 
}