virtpers.cpp

本课程主要介绍面向对象程序设计的方法和c++语言的基本概念。以c++语言中的面向对象机制为主。学习者在学习过程中可以通过大量的程序实例和相关练习

// virtpers.cpp
// virtual functions with person class
#include <iostream>
using namespace std;
////////////////////////////////////////////////////////////////
class person                         //person class
   {
   protected:
      char name[40];
   public:
      void getName()
         { cout << "   Enter name: "; cin >> name; }
      void putName()
         { cout << "Name is: " << name << endl; }
      virtual void getData() = 0;        //pure virtual func
      virtual bool isOutstanding() = 0;  //pure virtual func
   };
////////////////////////////////////////////////////////////////
class student : public person        //student class
   {
   private:
      float gpa;              //grade point average
   public:
      void getData()          //get student data from user
         {
         person::getName();
         cout << "   Enter student's GPA: "; cin >> gpa;
         }
      bool isOutstanding()
         { return (gpa > 3.5) ? true : false; }
   };
////////////////////////////////////////////////////////////////
class professor : public person      //professor class
   {
   private:
      int numPubs;             //number of papers published
   public:
      void getData()           //get professor data from user
         {
         person::getName();
         cout << "   Enter number of professor's publications: ";
         cin >> numPubs;
         }
      bool isOutstanding()
         { return (numPubs > 100) ? true : false; }
   };
////////////////////////////////////////////////////////////////
int main()
   {
   person* persPtr[100];     //array of pointers to persons
   int n = 0;                //number of persons on list
   char choice;
   
   do {
      cout << "Enter student or professor (s/p): ";
      cin >> choice;
      if(choice=='s')                  //put new student
         persPtr[n] = new student;     //   in array
      else                             //put new professor
         persPtr[n] = new professor;   //   in array
      persPtr[n++]->getData();         //get data for person
      cout << "   Enter another (y/n)? ";  //do another person?
      cin >> choice;                    
      } while( choice=='y' );          //cycle until not 'y'

   for(int j=0; j<n; j++)              //print names of all
      {                                //persons, and
      persPtr[j]->putName();           //say if outstanding
      if( persPtr[j]->isOutstanding() )
         cout << "   This person is outstanding\n";
      }
   return 0;
   }  //end main()