1. Inheritance
CT1513

2. Modifiers in inheritance
Private(-) data members and methods for a super class cant be accessible to the subclass
Protected (#) data members and methods for a super class accessible to the instances of the subclasses .
Public (+) data members and methods are accessible to everyone.

3. Using super methods
In subclass you can override (or redefine) a method That is already existed in super class.
If there is no override you can call a public method of a superclass by its name and appropriate parameter list.
If the sub override the super method you should call it by using the reserved key word super.methodsName()

4. Inheritance and Constructors
public class SubClass extends SuperClass { public SubClass(………….) super (………); } **the call of the super constructor must be the first statement. Note : if you do not include statement super(). The default constructor of super will be called if any or there will be an error

5. Not valid
No call | super();

6. valid

7. valid

8. valid

9. public class rectangle { private double length; private double width; //defoult constructor public rectangle() {length=width=0; } public rectangle( double w , double l){ setdimension(w,l); } public void setdimension( double w, double l){width=w; length=l; } public double getw(){return width;} public double getl(){return length;} public double area(){ return width*length;} public void print() {System.out.println("length =" + length+"width = " + width );} }

10. Create class called box inherits from rectangle having the following:
Private height ,, ge_height()
Default constructor and copy constructor to set
Setdimension();
Area();//2*L*W + L * H +W* H
Print();

12. Polymorphism
CT1513

13. Introduction to polymorphism

14. Static Binding Vs. Dynamic Binding
Binding means associating a method definition with its invocation
It can be also called early binding

17. Note ! A
A refrence variable from a class A A ref; Can point to an object of class B as well as an object of class C ref = new A(); ref = new B(); ref = new C(); B C

18. 100
200
300
1000

19. In same rectangle – box example