Question

定义一个接口shape，定义两个实现该接口的类（圆形类和长方形类），并在主类中使用这两个类的对象。

求解。

Answer 1

interface Shape {
public double getArea();
}
class Square implements Shape{
private double height=0;//长方形的边长
public Square(double height){
this.height=height;
}
public double getArea() {
return (height*height);
}

}
class Circle implements Shape{
private double r=0;//员的半径
private final static double PI=3.14;//圆周率
public Circle (double r){
this.r=r;
}
public double getArea() {

return PI*r*r;
}

}
public class Test{
public static void main(String[] args) {
Shape square =new Square(3);
Shape circle=new Circle(2);
System.out.println(square.getArea());
System.out.println(circle.getArea());
}
}

Answer 2

public interface Rectangle{ public double len;//定义长 public double wid//实现获得面积的方法 public double getArea(){ return this.getLen()*