(1) 创建一个Rectangle类，添加width和height两个成员变量

(2) 在Rectangle中添加两种方法分别计算矩形的周长和面积

(3) 编程利用Rectangle输出一个矩形的周长和面积

import java.util.Scanner;

class rectangle{

double width;

double height;

double area;

double length;

public double Area(double width,double height)//定义方法

{

area=width*height;

return area;

}

public double Length(double width,double height)

{

length=2*(width+height);

return length;

}

public static void main(String args[])

{

Scanner sc=new Scanner(System.in);

System.out.println("请输入长和高" );

double width=sc.nextDouble();

double height=sc.nextDouble();

rectangle re=new rectangle();

double length=re.Length(width,height);

double area=re.Area(width,height);

System.out.println("面积是"+area);

System.out.println("周长是"+length);

}