How to make these 3 classes? (Java)

Question

Class1 Shape

-color:String

Methods:

+getArea() : double

+toString(): String ---> Superclass defines the expected behaviors(public intertace) of all subclasses.

Program at the public interface.

Class2 Rectangle

-length: int

-width:int

Methods:

+getArea(): double

+toString ():String

Class3 Triangle

-base: int

-height:int

Methods:

+getArea():double

+tostring):StringB---->Subclasses provide the

actual Implementations.

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Hint :

**

* Superclass Shape maintain the common properties of all shapes

*/

public class Shape {

// Private member variable

private String color;

/** Constructs a Shape instance with the given color */

public Shape (String color) {

______________________;

}

/** Returns a self-descriptive string */

@Override

public String toString() {

_____________________;

/** All shapes must provide a method called getArea() */

public double getArea() {

// We have a problem here!

// We need to return some value to compile the program.

__________________________________;

return 0;

}

}

/**

* The Rectangle class, subclass of Shape

*/

public class Rectangle extends Shape {

// Private member variables

private int length, width;

/** Constructs a Rectangle instance with the given color, length and width */

public Rectangle(String color, int length, int width) {

super(_________);

this._______ = _______;

this._______ = _______;

}

/** Returns a self-descriptive string */

@Override

public String toString() {

return "Rectangle[length=" + _____ + ",_______=" + ______ + "," + super.________() + "]";

/** Override the inherited getArea() to provide the proper implementation for rectangle */

@Override

public double getArea() {

return _______*_______;

}

}

/**

* The Triangle class, subclass of Shape

*/

public class Triangle extends Shape {

// Private member variables

private int base, height;

/** Constructs a Triangle instance with the given color, base and height */

public Triangle(String color, int base, int height) {

super(______);

this._____ = ______;

this._______ = _______;

}

/** Returns a self-descriptive string */

@Override

public String toString() {

return "Triangle[base=" + ______ + ",_______=" + _______ + "," + super.______() + "]";

/** Override the inherited getArea() to provide the proper implementation for triangle */

@Override

public double getArea() {

return 0.5*______*_______;

}

}

public class TestShape {

public static void main(String[] args) {

// Constructing a Shape instance poses problem!

Shape s3 = new _______("______");

System.out.println(____);

//Shape[color=green]

System.out.println("Area is " + s3.______()); // Invalid output

//Shape unknown! Cannot compute area!

//Area is 0.0

}

}

Answer 1

//******** Shapes.txt *************//

abstract class Shape

{

private String color;

public Shape( String Color) { color = new String(Color); }

public String GetColor() { return(color); }

public abstract double getArea() ;

public abstract String toString();

}

//********** Rectangle.java ************//

class Rectangle extends Shape

{

protected double length;

protected double width;

public Rectangle( double L, double w, String color )

{

super(color);

length = L;

width = w;

}

public double getArea() { return(length*width); }

@Override public String toString()

{

return( new String (( length + "," + width )));

}

double GetLength() { return(length); }

double GetWidth() { return(width); }

}

//******* Triangle.java ***************//

class Triangle extends Shape

{

protected double base;

protected double height;

Triangle ( double B, double h, String color)

{

super(color);

base = B;

height = h;

}

public double GetBase() { return(base); }

public double GetHeight() { return(height); }

public double getArea() { return( (base*height)/2 ); }

@Override public String toString()

{

return ( new String( ( base + "," + height)));

}

}

//********* Circle.java *****************//

import java.math.*;

class Circle extends Shape

{

protected double radius;

public Circle ( double R, String color)

{

super(color);

radius=R;

}

public double GetRadius() { return(radius); }

public double GetDiameter() {return(radius*2); }

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

@Override public String toString()

{

return( (new String(" "+radius )).trim());

}

}

//*********** main *****************//

class MainShape

{

public static void main( String args[])

{

Rectangle rectangle = new Rectangle( 6,5,"ORANGE");

Triangle triangle = new Triangle( 10,5,"PURPLE");

Circle circle = new Circle( 10,"GREEN");

System.out.println(" Rectange has area " + rectangle.getArea()

+ " with dimensions " + rectangle.toString()

+ " and color " + rectangle.GetColor()

);

System.out.println(" Triangle has area " + triangle.getArea()

+ " with dimensions " + triangle.toString()

+ " and color " + triangle.GetColor()

);

System.out.println(" Circle has area " + circle.getArea()

+ " with dimensions " + circle.toString()

+ " and color " + circle.GetColor()

);

}

}