p401 12.2 虚函数.cpp

谭浩强 《C++ 程序设计》第三版的部分课后练习题源码

#include<iostream>
using namespace std;
#include<string>
class Student
{
      private:
              int num;
              string name;
              float score;
     public:
            Student(int,string,float);
            virtual void display();         
      
};      
      
Student::Student(int n,string nam,float s)
{
       num=n;
       name=nam;
       score=s;
       
}                       
                   
void Student::display()
{
     cout<<"num="<<num<<"name="<<name<<"score="<<score<<endl;
}     
     
 class Graduate:public Student
{ 
       
      public:
             Graduate(int a=0,string b='\0',float c=0,float d=0): Student(a,b,c),pay(d){}
             void display();
       private:
               float pay;
};    

void  Graduate::display()
{
      Student::display();
      cout<<"pay="<<pay<<endl;
}       
      
      
    int main()
    {
        Student stud(1001,"liw",56);
        Graduate gra(2001,"wang",20.4,987.3);
        Student *s=&stud;
        s->display();
        cout<<endl;
        s=&gra;
        s->display();
        
         system("pause");
         return 0;
        
        
        }