Question

Using the IST Linux system create the following Java command line inheritance application Lab4. Create the following project Java files: Point.java, Shape.java, Circle.java, Triangle.java, Rectangle.java, and Lab4.java

Point.java will contain two coordinates x and y. This will be reused to create point objects to draw all the shapes.

Shape.java will be the parent class and will contain a Point type.

Circle.java, Triangle.java, Rectangle.java will all be children of Shapes.java class

Each class (Circle, Triangle, Rectangle) will contain the private class point type variables needed to draw the shape.

Each class (Circle, Triangle, Rectangle) will contain two constructor methods

constructor no input arguments but will set (hardcoded) the private point variables needed to draw the shape. It will also print out the shape type and the points set for that shape.

constructor the number of point type arguments needed to set the private point variables needed to draw the shape.  It will also print out the shape type and the points set for that shape.

Lab4.java will be the starting point for running the program

Lab4.java will create three objects one from the Circle class, one from Triangle class, and one from Rectangle class that calls the no input argument constructor 1 containing hardcoded points

Lab4.java will create another three objects one from the Circle class, one from Triangle class, and one from Rectangle class that will call constructor 2 and pass in the point type variables needed to draw the shape.

public class Lab41 public static void main (String[] args){ Circle c1 - new Circle(); Point p1 - new Point(4, 5); Circle c22 = new Circle(p1);

Answer 1

// Point.java : Point class with x-axis and y-axis value as attribute

public class Point {

int x;
int y;

public Point(int x, int y) {
this.x = x;
this.y = y;
}
}

// Shape.java : Parent Class for all shapes contining one Point attribute

public class Shape {

protected Point point;

}

// Circle.java : Circle class is child of Shape class containing additional radius attribute

public class Circle extends Shape {

private int radius;

public Circle() {
point = new Point(2,3);
radius = 2;
System.out.println("Circle Point: X:"+point.x+ " Y:"+point.y);
System.out.println("Circle radius:"+radius);
}

public Circle(Point point) {
super();
this.point = point;
radius = 5;
System.out.println("Circle Point: X:"+point.x+ " Y:"+point.y);
System.out.println("Circle radius:"+radius);
}
}

//Triangle.java : Triangle is child of Shape class containing additional two points to draw

public class Triangle extends Shape {

private Point point2;
private Point point3;

public Triangle() {
point = new Point(1,1);
point2 = new Point(2,2);
point3 = new Point(1,3);

System.out.println("Triangle Point-1: X:"+point.x+ " Y:"+point.y);
System.out.println("Triangle Point-2: X:"+point2.x+ " Y:"+point2.y);
System.out.println("Triangle Point-3: X:"+point3.x+ " Y:"+point3.y);
}

public Triangle(Point point1, Point point2, Point point3) {
point = point1;
this.point2 = point2;
this.point3 = point3;

System.out.println("Triangle Point-1: X:"+point.x+ " Y:"+point.y);
System.out.println("Triangle Point-2: X:"+point2.x+ " Y:"+point2.y);
System.out.println("Triangle Point-3: X:"+point3.x+ " Y:"+point3.y);
}
}

//Rectangle.java : Rectangle is child of Shape class containing additional 3 points to draw the shape

public class Rectangle extends Shape {

private Point point2;
private Point point3;
private Point point4;

public Rectangle() {
point = new Point(1,1);
point2 = new Point(1,2);
point3 = new Point(2,1);
point4 = new Point(2,2);
System.out.println("Rectangle Point-1: X:"+point.x+ " Y:"+point.y);
System.out.println("Rectangle Point-2: X:"+point2.x+ " Y:"+point2.y);
System.out.println("Rectangle Point-3: X:"+point3.x+ " Y:"+point3.y);
System.out.println("Rectangle Point-4: X:"+point4.x+ " Y:"+point4.y);
}

public Rectangle(Point point1, Point point2, Point point3, Point point4) {
super();
point = point1;
this.point2 = point2;
this.point3 = point3;
this.point4 = point4;

System.out.println("Rectangle Point-1: X:"+point.x+ " Y:"+point.y);
System.out.println("Rectangle Point-2: X:"+point2.x+ " Y:"+point2.y);
System.out.println("Rectangle Point-3: X:"+point3.x+ " Y:"+point3.y);
System.out.println("Rectangle Point-4: X:"+point4.x+ " Y:"+point4.y);
}

}

//Lab4.java : Lab4 is execution point of the complete assignment

public class Lab4 {

public static void main(String[] args) {
Circle c1 = new Circle();
Point p1 = new Point(4, 5);
Circle c22 = new Circle(p1);

Triangle t1 = new Triangle();
Point p2 = new Point(1,1);
Point p3 = new Point(1,7);
Triangle t2 = new Triangle(p1, p2, p3);

Rectangle r1 = new Rectangle();
Point p4 = new Point(9,5);
Rectangle r2 = new Rectangle(p1, p2, p3, p4);

}
}

// This application teaches us one of the Object oriented concepts called as "Inheritance".

// In this we separate out the common property in a parent class and all child class inherit it from parent.

// We use extends keyword to inherit propety of another class.

// Instructions for execution :

// Place all classes in different .java files. file names are mentioned in comment in bold.

//on command line we can refer all java files by specifying *.java in respected folder.

// for compilation execute >javac *.java

// to run the assignment execute >java Lab4

// It should give following output

// Circle Point: X:2 Y:3

// Circle radius:2

// Circle Point: X:4 Y:5

// Circle radius:5

// Triangle Point-1: X:1 Y:1

// Triangle Point-2: X:2 Y:2

// Triangle Point-3: X:1 Y:3

// Triangle Point-1: X:4 Y:5

// Triangle Point-2: X:1 Y:1

// Triangle Point-3: X:1 Y:7

// Rectangle Point-1: X:1 Y:1

// Rectangle Point-2: X:1 Y:2

// Rectangle Point-3: X:2 Y:1

// Rectangle Point-4: X:2 Y:2

// Rectangle Point-1: X:4 Y:5

// Rectangle Point-2: X:1 Y:1

// Rectangle Point-3: X:1 Y:7

// Rectangle Point-4: X:9 Y:5