Program to Calculate Area and Circumference of Circle in Java Example

This example is used to calculate the area and circumference of a circle with given radius. The class Circle contains the field radius and methods setData (), area ()and circumference ().The statement.

Circle obj = new Circle();

creates a Circle object in memory and assign it to the reference variable obj,

The statement,

obj.setData(3.5) ;

assigns the radius field of the Circle object to 3.5 using the reference variable obj.

The statement,

obj.area ();

obj.circumference() ;

calculates the area and circumference of the corresponding Circle object, which is finally displayed.

class circle 
 { 
      double radius; //radius of circle 
      void setData(double r) 
      { 
         radius = r; 
      } 
      void area () 
      { 
         double circleArea = Math.PI * radius *radius; 
         System.out.println("Area of circle is = " + circleArea); 
      } 
      void circumference() 
      { 
         double cir = 2 * Math.PI * radius ; 
         System.out.println("circumference of circle is = " + cir); 
      } 
       
   } 
   public class AreaAndCircumference 
 { 
      public static void main(String[] args) 
      { 
        
         circle obj = new circle(); 
         obj.setData(3.5 );  //call setData method 
         obj.area( );  //call area method 
         obj.circumference( );  //call circumference method 
      } 
 }