深入面向对象1——继承总结

import java.util.Scanner;
class Jvxing{
	public static int width,length;  //矩形的长宽
	public static int zhouchang(){     //求周长
		return (length+width)*2;
	}
}
class Zhengfx extends Jvxin{  //子类继承jvxing父类
	public static int length;
	public static int zhouchang(){
		return length*4;
	}	
	public Zhengfx(int length){  //子类中重写父类方法求周长的方法
		this.length=length;
	} 
	public static int area(){  //求面积
		return length*length;
	}	
}
public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner shuru=new Scanner(System.in);
		int z=shuru.nextInt();
		Zhengfx x=new Zhengfx(z);      //创建子类的对象
		System.out.println("正方形的面积是");		
		System.out.println(x.area());
		System.out.println("正方形的周长是");		
		System.out.println(x.zhouchang());	
	}

}