shape.java

贪食蛇的实现源码

package array;

public class Shape {

	/**
	 * @param 1、写一个父类Shape他有两个属性x、y，三个子类Rectangle，
	 * Circle, triangle，Rectangle有两个属性width和length. Circle有一个
	 * 属性radius，shape有一个方法draw()，测试一下多态的例子。
	 * 
	 */
	private double x;private double y;protected double area;
	/*public Shape(double x,double y)
	{
		this.x=x;
		this.y=y;
	}
	public Shape(){}*/
   public void draw(){
		//System.out.println("please draw the shape!!output the shape'area:"+area);
	                  }
	public static void main(String[] args) {
		Shape[] sh={
				new Rectangle(2.0,3),
				new Triangle(2.5,4.0),
				new Circle(2.05)
				};
		for(int i=0;i<sh.length;i++){
			sh[i].draw();
			}
		Rectangle tri=new Rectangle();//逐级调默认的三个构造方法
		
		tri.draw();
	}
	}
	class  Rectangle extends Shape{
		private double width;private double length;private double area;
		Rectangle(){
			this(3.2);
		}
		Rectangle(double width){
			this(width,2.3);
		}
		Rectangle(double width,double length){
			this.width=width;
			this.length=length;
			
		}
		public void draw(){
			area=width*length;
			System.out.println("this Rectangle'area is:"+area);
		}
	}
	class Triangle extends Shape{
		private double width;
		private double high;//private double area;
		Triangle(double width,double high){
			this.width=width;
			this.high=high;
		}
		public void draw(){
			area=width*high/2;
			System.out.println("this Triangle'area is:"+area);
		}
	}
	class  Circle extends Shape{
		private double radius;
		public static final double PI=3.1415926;
		Circle(double radius){
			this.radius=radius;
		}
		public void draw(){
			area=PI *radius*radius;
			System.out.println("this Circle'area is:"+area);
		}
	}