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Posts : 113
Join date : 2011-08-01
 |  Subject: polymorphism in JAVA eclipse  Wed Jan 31, 2018 9:20 pm | |
| polymorphism, exampled via the shape class, and its overridden surface area methode, in the Main class. shape super class : - Code:
package com.shapes.objects;
public class Shape {
public Shape() {
// TODO Auto-generated constructor stub
}
public double surfaceArea() {
return 0;
}
}
square sub class of shape - Code:
package com.shapes.objects;
public class Square extends Shape {
private double height;
public double getHeight() {
return height;
}
public void setHeight(double height) {
this.height = height;
}
public Square(double height) {
this.height = height;
}
public double surfaceArea() {
return height*height;
}
}
rectangle sub class of square - Code:
package com.shapes.objects;
public class Rectangle extends Square{
private double width;
public double getWidth() {
return width;
}
public void setWidth(double width) {
this.width = width;
}
public Rectangle(double height, double width) {
super(height);
this.width = width;
}
@Override
public double surfaceArea() {
return super.getHeight()*width;
}
}
triangle sub class of shape - Code:
package com.shapes.objects;
public class Triangle extends Shape {
private double height;
private double width;
public Triangle(double height, double width) {
super();
this.height = height;
this.width = width;
}
public double getHeight() {
return height;
}
public void setHeight(double height) {
this.height = height;
}
public double getWidth() {
return width;
}
public void setWidth(double width) {
this.width = width;
}
@Override
public double surfaceArea() {
return (height*width)/2;
}
}
circle class extends (sub class of) shape super class: - Code:
package com.shapes.objects;
public class Circle extends Shape {
private double Radius;
public double getRadius() {
return Radius;
}
public void setRadius(double radius) {
Radius = radius;
}
public Circle(double radius) {
super();
Radius = radius;
}
public double surfaceArea() {
return Radius*Radius*3.1415;
}
}
main class plays around with the classes using polymorphism to refer to all objects as a shape and using the override methods of the sub classes even though they were declared as the super class : - Code:
package com.shapes.objects;
import java.util.Scanner;
import org.w3c.dom.css.Rect;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Shape sh1 = new Shape();
System.out.println(sh1.surfaceArea());
Rectangle rec1 = new Rectangle(10, 5);
System.out.println(rec1.surfaceArea());
Shape sh2 = rec1;
System.out.println(sh2.surfaceArea());
Shape[] shapeArray = new Shape[5];
for (int i = 0; i < shapeArray.length; i++) {
System.out.println("enter shape");
Scanner scanner2 = new Scanner(System.in);
String x2 = scanner2.next();
shapeArray[i] = getShape(x2);
System.out.println(shapeArray[i].surfaceArea());
}
}
public static Shape getShape(String form) {
Shape result = null;
Scanner scanner11 = new Scanner(System.in);
switch (form) {
case "square":
System.out.println("enter square side size");
double x1 = scanner11.nextDouble();
return new Square(x1);
case "circle":
System.out.println("enter circle radius");
double Radius1 = scanner11.nextDouble();
return new Circle(Radius1);
case "rectangle":
System.out.println("enter rectangle height");
double height = scanner11.nextDouble();
System.out.println("enter rectangle width");
double width = scanner11.nextDouble();
return new Rectangle(height, width);
case "triangle":
System.out.println("enter triangle height");
double Theight = scanner11.nextDouble();
System.out.println("enter triangle width");
double Twidth = scanner11.nextDouble();
return new Triangle(Theight, Twidth);
default:
break;
}
return result;
}
}
 _________________ kurayami no kagi _____  |
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