Question

You will be creating a driver class and 5 class files for this assignment. The classes are Shape2D (the parent class), Circle, Triangle, and Rectangle (all children of Shape2D) and Square (child of Rectangle).

Be sure to include a message to the user explaining the purpose of the program before any other printing to the screen.

Within the driver class, please complete the following tasks:

Instantiate a Circle object with 1 side and a radius of 4; print it

Update the radius of the Circle to 7; reprint the circle using a heading like “Updated circle: “

Instantiate an equilateral Triangle object with 3 sides and a side length of 3; print it

Instantiate a Rectangle object with 4 sides, a length of 2 and a width of 5; print it

Instantiate a Square object with 4 sides and side lengths of 6; print it

Within each inherited (child) object class you must include the following methods unless inherited from the parent class or it provides updated functionality relevant to the class:

A constructor method that accepts parameters including the number of sides the object has and all values required to calculate area and perimeter/circumference.

Getter and setter methods for all instance data except the number of sides.

Methods to calculate the area and perimeter/circumference.

A toString method which provides a description (one or two lines) about the object that includes the number of sides it has, its area, and its perimeter/circumference.

All calculated values must be printed with up to 2 decimal places.

Sample format: A circle is an object with 1 side(s). It has a radius of 4, an area of 50.27 and a circumference of 25.13

Include clear comments throughout the program that explain the well named variables and what functionality the various lines/small sections of code are completing as related to the execution of the program.

Answer 1

package January;

import java.text.DecimalFormat;

// Class Shape2D definition

abstract class Shape2D

{

// Instance variable to store data

int numberOfSides;

double area;

double perimeter;

// Default constructor

Shape2D()

{

numberOfSides = 0;

area = 0.0;

perimeter = 0.0;

}// End of default constructor

// Parameterized constructor

Shape2D(int sides)

{

numberOfSides = sides;

area = 0.0;

perimeter = 0.0;

}// End of parameterized constructor

// Method to return number of sizes

int getSides()

{

return numberOfSides;

}// End of method

// Abstract methods

abstract void findArea();

abstract void findPerimeter();

}// End of class

// Class Circle derived from Shape2D

class Circle extends Shape2D

{

// Creates an object of the class DecimalFormat to display data with 2 decimal places  

DecimalFormat f = new DecimalFormat("#####.00");

// Instance variable to store data

final double PI = 3.141;

double radius;

// Default constructor

Circle()

{

super();

radius = 0.0;

}// End of default constructor

// Parameterized constructor

Circle(int side, int radius)

{

super(side);

this.radius = radius;

}// End of parameterized constructor

// Method to set radius

void setRadius(double r)

{

radius = r;

}// End of method

// Method to return radius

double getRadius()

{

return radius;

}// End of method

// Override Method to calculate area

void findArea()

{

area = PI * radius * radius;

}// End of method

// Override Method to calculate perimeter

void findPerimeter()

{

perimeter = 2.0 * PI * radius;

}// End of method

// Method to return area

double getArea()

{

findArea();

return area;

}// End of method

// Method to return perimeter

double getPerimeter()

{

findPerimeter();

return perimeter;

}// End of method

// Overrides toString() method

public String toString()

{

return "\n A circle is an object with " + getSides() + " side(s)." + " It has a radius of " + f.format(getRadius()) +

", an area of " + f.format(getArea()) + " and a circumference of " + f.format(getPerimeter());

}// End of method

}// End of class

// Class Triangle derived from Shape2D

class Triangle extends Shape2D

{

// Instance variable to store data

double side;

// Creates an object of the class DecimalFormat to display data with 2 decimal places

DecimalFormat f = new DecimalFormat("#####.00");

// Default constructor

Triangle()

{

super();

side = 0.0;

}// End of constructor

// Parameterized constructor

Triangle(int sides, double side)

{

super(sides);

this.side = side;

}// End of parameterized constructor

// Method to set side

void setSide(double s)

{

side = s;

}// End of method

// Method to return side

double getSide()

{

return side;

}// End of method

// Override Method to calculate area

void findArea()

{

area = (Math.sqrt(3) * side * side) / 4.0;

}// End of method

// Override Method to calculate perimeter

void findPerimeter()

{

perimeter = 3.0 * side;

}// End of method

// Method to return area

double getArea()

{

return area;

}// End of method

// Method to return perimeter

double getPerimeter()

{

return perimeter;

}// End of method

// Overrides toString() method

public String toString()

{

return "\n A equilateral triangle is an object with " + getSides() + " side(s)." + " It has a radius of " +

f.format(getSide()) + ", an area of " + f.format(getArea()) +

" and a circumference of " + f.format(getPerimeter());

}// End of method

}// End of class

class Rectangle extends Shape2D

{

// Instance variable to store data

double length, width;

// Creates an object of the class DecimalFormat to display data with 2 decimal places

DecimalFormat f = new DecimalFormat("#####.00");

// Default constructor

Rectangle()

{

super();

length = width = 0.0;

}// End of constructor

// Parameterized constructor

Rectangle(int sides, double length, double width)

{

super(sides);

this.length = length;

this.width = width;

}// End of parameterized constructor

// Method to set length

void setLength(double l)

{

length = l;

}// End of method

// Method to return length

double getLength()

{

return length;

}// End of method

// Method to set width

void setWidth(double w)

{

width = w;

}// End of method

// Method to return width

double getWidth()

{

return width;

}// End of method

// Override Method to calculate area

void findArea()

{

area = length * width;

}// End of method

// Override Method to calculate perimeter

void findPerimeter()

{

perimeter = 2.0 * (length + width);

}// End of method

// Method to return area

double getArea()

{

return area;

}// End of method

// Method to return perimeter

double getPerimeter()

{

return perimeter;

}// End of method

// Overrides toString() method

public String toString()

{

return "\n A Rectangle is an object with " + getSides() + " side(s)." + " It has lenght of " +

f.format(getLength()) + ", and width of " + f.format(getWidth()) +

", an area of " + f.format(getArea()) + " and a circumference of " + f.format(getPerimeter());

}// End of method

}// End of class

class Square extends Shape2D

{

// Instance variable to store data

double side;

// Creates an object of the class DecimalFormat to display data with 2 decimal places

DecimalFormat f = new DecimalFormat("#####.00");

// Default constructor

Square()

{

super();

side = 0.0;

}// End of constructor

// Parameterized constructor

Square(int sides, double side)

{

super(sides);

this.side = side;

}// End of parameterized constructor

// Method to set side

void setSide(double s)

{

side = s;

}// End of method

// Method to return side

double getSide()

{

return side;

}// End of method

// Override Method to calculate area

void findArea()

{

area = Math.pow(side, 2);

}// End of method

// Override Method to calculate perimeter

void findPerimeter()

{

perimeter = 4.0 * side;

}// End of method

// Method to return area

double getArea()

{

return area;

}// End of method

// Method to return perimeter

double getPerimeter()

{

return perimeter;

}// End of method

// Overrides toString() method

public String toString()

{

return "\n A square is an object with " + getSides() + " side(s)." + " It has a side of " +

f.format(getSide()) + ", an area of " + f.format(getArea()) +

" and a circumference of " + f.format(getPerimeter());

}// End of method

}// End of class

// Driver class Shape2DDemo definition

public class Shape2DDemo

{

// main method definition

public static void main(String[] args)

{

// Creates an object of Circle class with parameterized constructor

Circle circle = new Circle(1, 4);

System.out.println(circle);

circle.setRadius(7.0);

System.out.println("Updated circle: " + circle);

// Creates an object of Triangle class with parameterized constructor

Shape2D triangle = new Triangle(3, 3.0);

System.out.println(triangle);

// Creates an object of Rectangle class with parameterized constructor

Shape2D rectangle = new Rectangle(4, 2.0, 5.0);

System.out.println(rectangle);

// Creates an object of Square class with parameterized constructor

Shape2D square = new Square(4, 6.0);

System.out.println(square);

}// End of main function

}// End of class

Sample Output:

A circle is an object with 1 side(s). It has a radius of 4.00, an area of 50.26 and a circumference of 25.13
Updated circle:
A circle is an object with 1 side(s). It has a radius of 7.00, an area of 153.91 and a circumference of 43.97

A equilateral triangle is an object with 3 side(s). It has a radius of 3.00, an area of .00 and a circumference of .00

A Rectangle is an object with 4 side(s). It has lenght of 2.00, and width of 5.00, an area of .00 and a circumference of .00

A square is an object with 4 side(s). It has a side of 6.00, an area of .00 and a circumference of .00