Comparing Object-Oriented Languages
Shape
The Shape example creates a more complicated class structure that includes code to illustrate the object-oriented concept of inheritance. You create four separate classes: Shape, Rectangle, Circle, and TestShape. The primary purpose of this example is to illustrate how the classes are used together in the context of inheritance and how to create a primary application.
//Shape
public abstract class Shape{
protected double area;
public abstract double getArea();
}
//Rectangle
public class Rectangle extends Shape{
private double length;
private double width;
public Rectangle(double l, double w){
length = l;
width = w;
}
public double getArea() {
area = length*width;
return (area);
}
}
//Circle
public class Circle extends Shape{
private double radius;
public Circle(double r) {
radius = r;
}
public double getArea() {
area = 3.14*(radius*radius);
return (area);
}
}
//TestShape
public class testShape {
public static void main(String args[]) {
Circle circle = new Circle(5);
Rectangle rectangle = new Rectangle(4,5);
}
}
Listing 3a: Java Code for Shape
//Shape
public abstract class Shape{
protected double area;
public abstract double getArea();
}
//Rectangle
public class Rectangle : Shape{
private double length;
private double width;
public Rectangle(double l, double w){
length = l;
width = w;
}
public override double getArea() {
area = length*width;
return (area);
}
}
//Circle
public class Circle : Shape {
private double radius;
public Circle(double r) {
radius = r;
}
public override double getArea() {
area = 3.14*(radius*radius);
return (area);
}
}
//TestShape
public class TestShape {
public static void Main() {
Circle circle = new Circle(5);
Rectangle rectangle = new Rectangle(4,5);
}
}
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This article was originally published on December 6, 2007
