w4-张思渊-202401070104

w4/ShapeUtil.java

@@ -0,0 +1,54 @@
+abstract class Shape{
+	public abstract double getArea();
+}
+
+class Circle extends Shape{
+	private double radius;
+	public Circle(double radius){
+		this.radius = radius;
+	}
+	@Override
+	public double getArea(){
+		return Math.PI*radius*radius;
+	}
+}
+
+class Rectangle extends Shape{
+	private double length;
+	private double height;
+	public Rectangle(double length,double height){
+		this.length=length;
+		this.height=height;
+	}
+	@Override
+	public double getArea(){
+		return length*height;
+	}
+}
+
+class Triangle extends Shape{
+	private double base;
+	private double height;
+	public Triangle(double base,double height){
+		this.base=base;
+		this.height=height;
+	}
+	@Override
+	public double getArea(){
+		return base*height/2;
+	}
+}
+
+public class ShapeUtil{
+	public static void printArea(Shape shape){
+		System.out.printf("ĂćťýĘÇ%.2f%n",shape.getArea());
+	}
+	public static void main(String[] args){
+	Shape circle = new Circle(5.0);
+	Shape rectangle = new Rectangle(10.0,20.0);
+	Shape triangle = new Triangle(3.0,4.0);
+	printArea(circle);
+	printArea(rectangle);
+	printArea(triangle);
+	}
+}