java 7

 import java.util.*;
public class test {
        

    public test() {
    }
    
    public static void main(String[] args) {
        // TODO code application logic here
        Scanner sc = new Scanner(System.in);
        System.out.println("输入半径，长，宽");
        int r = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();
        MyCircle circle = new MyCircle();
        MyRectangle rect = new MyRectangle();
        System.out.println("圆的周长和面积分别为：");
        System.out.println(circle.Circum(r));
        System.out.println(circle.Area(r));
        System.out.println("矩形的周长和面积分别为：");
        System.out.println(rect.Circum(a, b));
        System.out.println(rect.Area(a, b));        
    }
}
//抽象类
abstract class MyShape{
	public abstract int Circum(int x, int y);
	public abstract double Area(int x, int y);
}
class MyRectangle extends MyShape{
	public int Circum(int x, int y){
		return 2*(x + y);
	}
	public double Area(int x, int y){
		return x*y;
	}
}
class MyCircle extends MyShape{
	//覆盖MyShape中的抽象方法Area（int, int）
	public int Circum(int x, int y){
		return 0;
	}
	public double Area(int x, int y){
		return 0.0;
	}
		public int Circum(int r){
			return (int)(2*Math.PI*r);
		}
		public double Area(int r){
			return Math.PI*r*r;
		}
	}