类—矩形面积

矩形的类

 1 public class Rec {
 2
 3
 4     double length;//长
 5     double wide;//宽
 6
 7     public double getArea(){
 8
 9         return (length * wide);
10
11     }
12
13     Rec(int length,int wide){
14
15         this.length = length;
16         this.wide = wide;
17     }
18
19     Rec(double length,double wide){
20
21         this.length = length;
22         this.wide = wide;
23     }
24
25 }

测试类，调用矩形类

 1 public class RecTest {
 2
 3     public static void main(String[] args) {
 4
 5         // 调用
 6
 7         Rec r = new Rec(4, 4);// 构造对象并初始化
 8
 9         System.out.println("矩形的面积是：" + r.getArea());
10
11     }
12 }

运行的结果：

矩形的面积是：16.0