The document discusses different types of inheritance in object-oriented programming including single, multilevel, hierarchical, and method overriding. Single inheritance refers to a subclass inheriting from a single superclass. Multilevel inheritance is a chain of inheritance with multiple subclasses. Hierarchical inheritance involves a superclass with multiple subclasses inheriting directly from it. Method overriding provides a specific implementation of a method defined in the superclass.

2.  Inheritance can be defined as the
process where one class acquires the
properties (methods and fields) of
another .
 The class which inherits the properties
of other is known as Subclass or Child
class or Derived class and the class
whose properties are inherited is
known as Super class or Parent class or
Base class .

3.  Single Inheritance,
 Multi Level Inheritance,
 Hierarchical Inheritance,
 Multiple Inheritance ,
 Hybrid Inheritance .
(java does not support multiple and
hybrid inheritance because a class cannot
extend more then main class in java).

4. When a class inherits another class , it
is known as a Single Inheritance.
Class A
Class B

5. import java.io.*;
import java.util.Scanner;
class cal_bill
{
double billpay;
void Bill(long units)
{
if(units<100)
billpay=units*1.20;
else if(units<=300)
billpay=(100*1.20)+((units-100)*2);
else
billpay=(100*1.20)+(200*2)+((units-300)*3);
}
}

6. class eb_bill extends cal_bill
{
public static void main(String args[])
{
long units;
Scanner sc=new Scanner(System.in);
System.out.println("enter the number of
units:");
units=sc.nextLong();
eb_bill b=new eb_bill();
b.Bill(units);
System.out.println("bill to pay:"+b.billpay);
}
}

7. enter the number of units:
420
bill to pay:880.0
enter the number of units:
175
bill to pay:270.0
enter the number of units:
89
bill to pay:106.8

8. When there is a chain of
inheritance , It is known as Multilevel
Inheritance .
Class A
Class B
Class C

9. import java.io.*;
import java.util.Scanner;
class A
{
int roll,m1,m2,m3;
Scanner s=new Scanner(System.in);
public void display()
{
System.out.println("enter roll number:");
roll=s.nextInt();
System.out.println("enter the mark1:");
m1=s.nextInt();
System.out.println("enter the mark2:");
m2=s.nextInt();
System.out.println("enter the mark3:");
m3=s.nextInt();
}
}

10. class B extends A
{
int tot,avg;
public void cal()
{
tot=m1+m2+m3;
System.out.println("the total is:"+tot);
avg=tot/3;
System.out.println("the average is:"+avg);
}
}
class C extends B
{
char grade;
public void result()
{
if (avg>90)
grade='O';
else if(avg<90 && avg>=60)
grade='D';
else
grade='U';
System.out.println("the grade is:"+grade);
}
}

11. public class mark_list {
public static void main(String args[])
{
C c=new C();
c.display();
c.cal();
c.result();
}
}
enter roll number:
5
enter the mark1:
85
enter the mark2:
91
enter the mark3:
79
the total is:255
the average is:85
the grade is:D

12. When two or more classes inherits a
single class , it is known as Hierarchical
Inheritance .
Class A
Class B Class C

13. import java.io.*;
import java.util.Scanner;
class X
{
int days;
Scanner l=new Scanner(System.in);
void details()
{
System.out.println("enter the number of days worked:");
days=l.nextInt();
}
}
class Y extends X
{
int d1=500,salary1;
public void supervisor()
{
System.out.println("the supervisor");
System.out.println("the salary for a day is:"+d1);
salary1=days*d1;
System.out.println("the salary for this month is:"+salary1);
}
}

14. class Z extends X
{
int d2=300,salary2;
public void worker()
{
System.out.println("the worker");
System.out.println("the salsry for a day is:"+d2);
salary2=days*d2;
System.out.println("the salary for this month is:"+salary2);
}
}
public class employee {
public static void main(String args[])
{
int emp_id=0;
Y obj1=new Y();
Z obj2=new Z();
Scanner e=new Scanner(System.in);
System.out.println("enter the employee id:");
emp_id=e.nextInt();
obj1.details();
if (emp_id<100)
obj1.supervisor();
else
obj2.worker();
}
}

15.  enter the employee id:
543
enter the number of days worked:
28
the worker
the salsry for a day is:300
the salary for this month is:0
 enter the employee id:
75
enter the number of days worked:
26
the supervisor
the salary for a day is:500
the salary for this month is:13000

16. If subclass (child class) has the same
method as described in parent class , it is
known as Method Overriding in java .
Method overriding is used to provide
specific implementation of a method
which is already provided by its super
class .
Method overriding is used for runtime
polymorphism .

17.  The method have the same name
as in the parent class .
 The method must have the same
parameter as in the parent class.
 There must be an IS-A
relationship (inheritance) .

18. import java.io.*;
class vehicle{
void run()
{
System.out.println("Vehicle is running");
}
}
class bike extends vehicle
{
void run()
{
System.out.println("Bike is running safely");
}

19. public static void main(String args[])
{
bike obj=new bike();
obj.run();
}
}
Bike is running safely

20. ANY
QUESTIONS?