A super class Circle has been defined to calculate the area of a circle. Define a subclass Volume
to calculate the volume of a cylinder.
The details of the members of both the classes are given below:
Class name : Circle
Data members/instance variables:
radius : to store the radius in decimals
area : to store the area of a circle
Methods / Member functions:
Circle( ... ) : parameterized constructor to assign values to the data members
void cal_area() : calculates the area of a circle (πr2)
void display( ) : to display the area of the circle
Class name :Volume
Data members/instance variables:
height : to store the height of the cylinder in decimals
volume : to store the volume of the cylinder in decimals
Methods / Member functions:
Volume( ... ) : parameterized constructor to assign values to the
data members of both the classes
double calculate( ) : to calculate and return the volume of the cylinder
using the formula (πr2h) where, r is the radius and
h is the height
void display( ) : to display the area of a circle and volume of a
cylinder
Assume that the super class Circle has been defined. Using the concept of inheritance,
specify the class Volume giving the details of the constructor(...), double calculate( ) and
void display( ).
The super class, main function and algorithm need NOT be written.
        

Solution:

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import java.util.*;
class Circle
{
  double radius;
  double area;
  Circle(double r){
      radius=r;
      area=0.0;
  }

  void cal_area(){
      double pi=3.14;
      area=pi*Math.pow(radius,2);
  }

  void display() {
      System.out.println("Area of the circle="+area);
  }
}
  
    
  
class Volume extends Circle {
  double height;
  double volume;
  Volume(double h,double r1)
  {
      super(r1);
      height=h;
      volume=0.0;
  }

  double calculate(){
      double pi=3.14;
      double r=super.radius;
      volume=pi*(r*r)*height;

      return volume;
  }

  void display()
  {
      super.display();
      System.out.println("Volume of the cylinder"+volume);
  }
}