纯作业代码——Java实现接口、继承

//该代码实现结果为如果设定的长和宽相等则实例化正方形（Square）的类，否则实例化矩形类。interface rect{public double area();public void getWidth(double Width);public void getHeight(double Height);}class Rectangle1 implements rect{double _width,_height;public void getWidth(double Width){_width=Width;}public void getHeight(double Height){_height=Height;}public double area(){return(_width*_height);}}class Square extends Rectangle1{public double area(){return(_width*_width);}}public class test1{//At here ,I use the super class to define rect1.static Rectangle1 rect1; //set the value of width and height,then judge the shape,and Print thempublic static void SetValue(double width ,double height){ if(width==height) rect1=new Square(); else rect1=new Rectangle1();rect1.getWidth(width);System.out.println("The Width value is :"+width+".");rect1.getHeight(height);System.out.println("The Height value is :"+height+".");if(width==height) System.out.println("The shape is Square!");else System.out.println("The shape is Rectangle!");}//get the result,and print itpublic static void CalcIt(){System.out.println("The result is :"+rect1.area()+".");}public static void main(String args[]){//set the width and heightSetValue(10,10);CalcIt();System.out.println('/n');//set the width and heightSetValue(10,50); CalcIt();}}

 

这是教材上的一道题。首先写了一个计算矩形的类，然后再让写一个正方形的类来继承矩形类。并且要求重写父类中的至少一个方法。

于是有了这段代码。

 

各位尽管点评。

 

 

 

ps:高等教育出版社的书，“不'错'~~~~(>_<)~~~~ ”