Java Constructor Exercises Questions

Design a class named Circle. Construct three circle objects with radius 2.0, 12, and 24 and displays the radius and area of each. A no-arg constructor set the default value of radius to 1. A getArea() function is used to return the area of circle. Now implement the class.

Logic of program
Part 1: Design a class named Circle.
Ans:
class Circle{


        }

Part 2: Construct three circle objects with radius 2.0, 12, and 24
Ans : 
      Circle obj1= new Circle(2.0);  
      Circle obj2= new Circle(12);  
      Circle obj3= new Circle(24); 
Note: object create only main funsion

    Circle(double x){
               redious =x;     
    }
paramiter radius pass when object create.

Part 3: displays the radius and area of each
Ans : 
Note: area=3.1416*redious*redious;
void display(){
    System.out.println("redious  "+redious);
    System.out.println("area  "+area);
    
}

Part 4: A no-arg constructor set the default value of radius to 1.
Ans : 
Circle(){
    redious =1;    
}

Part 5: A  getArea() function is used to return the area of circle
Ans : 
double getArea(){
     area=3.1416*redious*redious;
    return area;
}

class Circle{
    double redious;
    double area;
Circle(double x){
    redious =x;
     area=3.1416*redious*redious;
}
void display(){
    System.out.println("redious  "+redious);
    System.out.println("area  "+area);
    
}
Circle(){
    redious =1;    
}
double getArea(){
     area=3.1416*redious*redious;
    return area;
}

}
public class JavaApplication24 {  
    public static void main(String[] args) {
      Circle obj1= new Circle(2.0);  
      Circle obj2= new Circle(12);  
      Circle obj3= new Circle(24); 
      
      obj1.display();
      obj2.display();
      obj3.display();
      
       Circle obj4= new Circle();  
      Circle obj5= new Circle();  
      Circle obj6= new Circle(); 
      
      
      double arear= obj4.getArea();
       double arear2= obj5.getArea();
        double arear3= obj6.getArea();
        
       System.out.println("arear  "+arear);  
        System.out.println("arear2  "+arear2);
         System.out.println("arear3  "+arear3);
    }
    
}