//接口
public interface Shape{
public abstract double getPeremeter();
public abstract double getArea();
}
//矩形类
public class MyRect implements Shape{
private double width = 0; //宽
private double height = 0;//长
private double arc = 0;//对角线
public MyRect(double width, double height){
this.width = width;
this.height = height;
}
@Override
public double getPeremeter(){
return (width + height) * 2;
}
@Override
public double getArea(){
return width * height;
}
public void show(){
arc = Math.sqrt((width * width) + (height * height))
System.out.println("长:"+ height + " 宽:" + width + " 面积:" + getArea() + " 对角线:" + arc);
}
}
public class test{
public static void main(String [] args){
MyRect myRect = new MyRect(20, 30);
System.out.println("周长:" + myRect.getPeremeter());
System.out.println("面积:" + myRect.getArea());
myRect.show();
}
}
追问怎么做的呀?