testshape.java

与java有关的相关练习题目

public class TestShape{
	public static void main(String[] args){
		Shape[] ss=new Shape[3];
		ss[0]=new Rect(4,2);
		ss[1]=new Square(5);
		ss[2]=new Circle(10);
		
		for(int i=0;i<ss.length;i++){
			System.out.println(ss[i].line());
			System.out.println(ss[i].area());
		}
	}
}
abstract class Shape{
	public Shape(){}
	public abstract double line();
	public abstract double area();
}
class Rect extends Shape{
	private double x;
	private double y;
	public Rect(){}
	public Rect(double x,double y){
		this.x=x;
		this.y=y;
	}
	public double line(){
		return (x+y)*2;
	}
	public double area(){
		return x*y;
	}
}
class Square extends Rect{
	private double a;
	public Square(){}
	public Square(double a){
		this.a=a;
	}
	public double line(){
		return a*4;
	}
	public double area(){
		return a*a;
	}
}
class Circle extends Shape{
	private double r;
	public Circle(){}
	public Circle(double r){
		this.r=r;
	}
	public double line(){
		return 2*r*3.1415926;
	}
	public double area(){
		return r*r*3.1415926;
	}
}