Question

 //  Inheriting member functions
 // Please Make all changes as noted below:
 // 1) Make sayHello virtual function (hint this will be done in Person class
 // 2) Change main to create two Person pointer variables
 // 3) Set each pointer to one of the two objects already instantiated below
 // 4) Use the pointer variable to invoke the two sayHello() methods

 #include <iostream > 
 #include <string > 
 using namespace std ; 
  
 class Person { 
   protected : 
     string name; 
     int age ; 
   public : 
    Person () : name("" ) , age (0) 
     {cout << "New person created . " << endl ;} 
    Person ( string n , int a) 
     :name(n) , age(a) 
     {cout << "New person created . " << endl ;} 
  
    virtual void sayHello () { 
     cout << "Hello I am " << name << " . " ; 
     cout << "I am a person . " << endl ; 
    } 
    ~Person (){ cout << "Person deleted . " << endl ;} 
}; 
  
 class Student : public Person { 
   private : 
    double gpa ; 
   public :
    Student () : Person () , gpa (0.0) 
     {cout << "New student created . " << endl ;} 
    Student ( string n, int a , double g) 
     : Person (n , a) , gpa(g) 
      {cout << "New student created . " << endl ;} 
    ~Student (){ cout << "Student deleted . " << endl ;} 
    
        void sayHello () { 
         cout << "Hello I am " << name << " . " ; 
         cout << "I am a student . " << endl ; 
        }

 }; 
  
 int main () { 
  Person *p1, *p2;
  Person per1 ("John" , 22); 
  Student st1 ("Bob" , 20, 3.55); 
  
  p1 = &per1;
  p2 = &st1;
  
  p1->sayHello();   // same as (*p1).sayHello()
  p2->sayHello ();  // same as (*p2).sayHello()
  return 0; 
 }

Questions are on the top of code i.e. 1), 2), 3) and 4) to make changes in give code

Answer 1

All 4 are done

1) Person class has virtual method sayHello
2) Two pointer variable Person *p1 and *p2
3) They are initialised to Already created person and student object
4) They call sayHello() method.

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#include <iostream>

#include <string>

using namespace std ;

class Person {

protected :

string name;

int age ;

public :

Person () : name("" ) , age (0)

{cout << "New person created . " << endl ;}

Person ( string n , int a)

:name(n) , age(a)

{cout << "New person created . " << endl ;}

virtual void sayHello () {

cout << "Hello I am " << name << " . " ;

cout << "I am a person . " << endl ;

}

~Person (){ cout << "Person deleted . " << endl ;}

};

class Student : public Person {

private :

double gpa ;

public :

Student () : Person () , gpa (0.0)

{cout << "New student created . " << endl ;}

Student ( string n, int a , double g)

: Person (n , a) , gpa(g)

{cout << "New student created . " << endl ;}

~Student (){ cout << "Student deleted . " << endl ;}

void sayHello () {

cout << "Hello I am " << name << " . " ;

cout << "I am a student . " << endl ;

}

};

int main () {

Person *p1, *p2;

Person per1 ("John" , 22);

Student st1 ("Bob" , 20, 3.55);

p1 = &per1;

p2 = &st1;

p1->sayHello(); // same as (*p1).sayHello()

p2->sayHello (); // same as (*p2).sayHello()

return 0;

}

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SEE OUTPUT

PLEASE COMMENT if there is any concern.

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