Question

Q 4(b) 6 Marks] Write the code for a single Java class of your own choice that demonstrates the use of the following features in the Java language: Method overloadingg The use of super and this Identify clearly where in your code each of these points is being demonstrated Q 4(c) [6 Marks] Write an abstract Student class in Java which has a name, id_number, year and programme_code as member variables. Add a constructor to your class and a display() method, which prints out all information relating to a Student. Q 4(d) [10 Marks] Write a new class UndergradStudent, which inherits from the Student class of Q4(c) and has the following features An UndergradStudent has an array of Module objects Each Module has a module code (e.g. EE219), a module name and a constructor and display() method. Show the code for this Module class A constructor which takes an array of Module references as a parameter and also passes initialisation values to its parent's constructor. Override the display() method so that it also lists module information. In the above, avoid any unnecessarily duplication of code, for example, make use of the super reference, where applicable.

Q 4(b) 6 Marks] Write the code for a single Java class of your own choice that demonstrates the use of the following features in the Java language: Method overloadingg The use of super and this Identify clearly where in your code each of these points is being demonstrated Q 4(c) [6 Marks] Write an abstract Student class in Java which has a name, id_number, year and programme_code as member variables. Add a constructor to your class and a display() method, which prints out all information relating to a Student. Q 4(d) [10 Marks] Write a new class UndergradStudent, which inherits from the Student class of Q4(c) and has the following features An UndergradStudent has an array of Module objects Each Module has a module code (e.g. EE219), a module name and a constructor and display() method. Show the code for this Module class A constructor which takes an array of Module references as a parameter and also passes initialisation values to its parent's constructor. Override the display() method so that it also lists module information. In the above, avoid any unnecessarily duplication of code, for example, make use of the super reference, where applicable.

Answer 1

4. b)

i) Method Overloading Code

// Java program to demonstrate working of method
// overloading in Java.

public class Sum {

   // Overloaded sum(). This sum takes two int parameters
   public int sum(int x, int y)
   {
       return (x + y);
   }

   // Overloaded sum(). This sum takes three int parameters
   public int sum(int x, int y, int z)
   {
       return (x + y + z);
   }

   // Overloaded sum(). This sum takes two double parameters
   public double sum(double x, double y)
   {
       return (x + y);
   }

   // Driver code
   public static void main(String args[])
   {
       Sum s = new Sum();
       System.out.println(s.sum(10, 20));
       System.out.println(s.sum(10, 20, 30));
       System.out.println(s.sum(10.5, 20.5));
   }
}

ii) The use of this

// Program to illustrate this keyword
// is used to refer current class
class RR {
   // instance variable
   int a = 10;

   // static variable
   static int b = 20;

   void GFG()
   {
       // referring current class(i.e, class RR)
       // instance variable(i.e, a)
       this.a = 100;

       System.out.println(a);

       // referring current class(i.e, class RR)
       // static variable(i.e, b)
       this.b = 600;

       System.out.println(b);
   }

   public static void main(String[] args)
   {
       // Uncomment this and see here you get
       // Compile Time Error since cannot use
       // 'this' in static context.
       // this.a = 700;
       new RR().GFG();
   }
}

The use of super

// Program to illustrate super keyword
// refers super-class instance

class Parent {
   // instance variable
   int a = 10;

   // static variable
   static int b = 20;
}

class Base extends Parent {
   void rr()
   {
       // referring parent class(i.e, class Parent)
       // instance variable(i.e, a)
       System.out.println(super.a);

       // referring parent class(i.e, class Parent)
       // static variable(i.e, b)
       System.out.println(super.b);
   }

   public static void main(String[] args)
   {
       // Uncomment this and see here you get
       // Compile Time Error since cannot use 'super'
       // in static context.
       // super.a = 700;
       new Base().rr();
   }
}