Question

This lab is an exercise of using Java’s and C++’s dynamic binding features. The uncompleted programs to run in Java and in C++ are given below. Note that you need to create a driver class with the main method to run the Java program. Also, you need to write the main function to run the C++ program. Perform the following activities:

1. predict the output of the Java program.
2. run the Java program and compare your prediction to the actual output of the program.
3. Complete the C++ program such that it prints the same output as the Java program does. You need to use the given classes to generate the desired output.
4. Turn in your Java and C++ program files (.java and .cpp files) in Blackboard Learn.

The Java Program is:

class A

{ public void p()

{ System.out.println(“A.p”); }   public void q()

{ System.out.println(“A.q”); }   public void r()

{ p(); q(); }

}

class B extends A { public void p()

{ System.out.println(“B.p”); }

}

class C extends B

{ public void q()

{ System.out.println(“C.q”); }   public void r()

{ p(); q(); }

}

…

A a;

C c = new C(); a = c; a.r(); a = new B();

a.r(); a = new C();

a.r();

The C++ Program is:

class A

{ public:

virtual void p()

            { cout << “A.p” << endl; }        void q()          { cout << “A.q” << endl; }    virtual void r()

            { p(); q(); }

};

class B : public A

{ public:

void p()

            { cout << “B.p” << endl; }

}; class C : public B

{ public:

void q()

            { cout << “C.q” << endl; }          void r()

            { p(); q(); }

};

help me pls, i cant run java part. do i need to change something?

Answer 1

JAVA :

class A

{ public void p()

{ System.out.println(“A.p”); 

}  

 public void q()

{ System.out.println(“A.q”); 

}  

 public void r()

{ p();

  q(); 
}

}

class B extends A {

  public void p()

{ System.out.println(“B.p”); 

}

}

class C extends B

{ public void q()

{ System.out.println(“C.q”);

}  

 public void r()

{ p(); 

  q(); 

}

}

class Driver 

{ public static void main(String args[])

{

A a;

C c = new C(); 

a = c;

a.r();

a = new B();

a.r(); 

a = new C();

a.r();

}

}

C++ :

#include<iostream>

using namespace std;

class A

{ public : virtual void p()

            { cout << “A.p” << endl; 

}        

void q()          

{ cout << “A.q” << endl; 

}   

 virtual void r()

            { p();

 q(); 

}

};

class B : public A

{ public : void p()

            { cout << “B.p” << endl; 

}

}; 

class C : public B

{ public : void q()

            { cout << “C.q” << endl;

 }          

void r()

            { p(); 

q(); }

};

int main()

{

A a;

C c;

B b;

c.r();

b.r();

c.r();

}

Common Output of Java & C++ :

B.p

C.q

B.p

A.q

B.p

C.q