Question

write a completed program (included the main) for the Q: add an equals method to each of the Rectangle circle and triangle classes introduced in this chapter. two shapes are considered equal if their fields have equivalent values. based on

public class Circle implements Shape f private double radius; // Constructs a new circle with the given radius. public Circle (double radius) f this.radius - radius; // Returns the area of this circle. public double getArea) return Math.PI *radius * radius; // Returns the perimeter of this circle. public double getPerimeter() { return 2.0 *Math.PI *radius;

Answer 1

Note: Could you plz go through this code and let me know if u need any changes in this.Thank You
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// Shape.java

public interface Shape {
   public double getArea();

   public double getPerimeter();

}

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// Circle.java

public class Circle implements Shape {
   private double radius;

   public Circle(double radius) {
       this.radius = radius;
   }

   @Override
   public double getArea() {
       return Math.PI * radius * radius;
   }

   @Override
   public double getPerimeter() {
       return 2 * Math.PI * radius;
   }

   @Override
   public int hashCode() {
       final int prime = 31;
       int result = 1;
       long temp;
       temp = Double.doubleToLongBits(radius);
       result = prime * result + (int) (temp ^ (temp >>> 32));
       return result;
   }

   public boolean equals(Circle other) {
       if (Double.doubleToLongBits(radius) != Double
               .doubleToLongBits(other.radius))
           return false;
       return true;
   }
  
  

}

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// Rectangle.java

public class Rectangle implements Shape {
   private double width;
   private double height;

   public Rectangle(double width, double height) {
       this.width = width;
       this.height = height;
   }

   @Override
   public double getArea() {

       return width * height;
   }

   @Override
   public double getPerimeter() {
       return 2 * (width + height);
   }

   public boolean equals(Rectangle other) {
       if (Double.doubleToLongBits(height) != Double
               .doubleToLongBits(other.height))
           return false;
       if (Double.doubleToLongBits(width) != Double
               .doubleToLongBits(other.width))
           return false;
       return true;
   }

}
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// Triangle.java

public class Triangle implements Shape {
   private double a;
   private double b;
   private double c;

   public Triangle(double a, double b, double c) {
       this.a = a;
       this.b = b;
       this.c = c;
   }

   @Override
   public double getArea() {
       double p;
       double area;
       p = (a + b + c) / 2;
       area = Math.sqrt(p * (p - a) * (p - b) * (p - c));
       return area;
   }

   @Override
   public double getPerimeter() {

       return a + b + c;
   }

   @Override
   public int hashCode() {
       final int prime = 31;
       int result = 1;
       long temp;
       temp = Double.doubleToLongBits(a);
       result = prime * result + (int) (temp ^ (temp >>> 32));
       temp = Double.doubleToLongBits(b);
       result = prime * result + (int) (temp ^ (temp >>> 32));
       temp = Double.doubleToLongBits(c);
       result = prime * result + (int) (temp ^ (temp >>> 32));
       return result;
   }

   public boolean equals(Triangle other) {
       if (Double.doubleToLongBits(a) != Double.doubleToLongBits(other.a))
           return false;
       if (Double.doubleToLongBits(b) != Double.doubleToLongBits(other.b))
           return false;
       if (Double.doubleToLongBits(c) != Double.doubleToLongBits(other.c))
           return false;
       return true;
   }
  

}
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// Test.java

import java.util.ArrayList;

public class Test {

   public static void main(String[] args) {
       ArrayList<Shape> arl = new ArrayList<Shape>();
       arl.add(new Circle(5.5));
       arl.add(new Rectangle(4, 7));
       arl.add(new Triangle(3, 4, 5));
       for (int i = 0; i < arl.size(); i++) {
           if (arl.get(i) instanceof Circle) {
               System.out.println("Circle :");
               System.out.println("Area :" + arl.get(i).getArea());
               System.out.println("Perimeter :" + arl.get(i).getPerimeter());
           }
           if (arl.get(i) instanceof Rectangle) {
               System.out.println("Rectangle :");
               System.out.println("Area :" + arl.get(i).getArea());
               System.out.println("Perimeter :" + arl.get(i).getPerimeter());
           }
           if (arl.get(i) instanceof Triangle) {
               System.out.println("Triangle :");
               System.out.println("Area :" + arl.get(i).getArea());
               System.out.println("Perimeter :" + arl.get(i).getPerimeter());
           }
       }

   }

}
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Output:

Circle :
Area :95.03317777109123
Perimeter :34.55751918948772
Rectangle :
Area :28.0
Perimeter :22.0
Triangle :
Area :6.0
Perimeter :12.0

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