rectangledemo1.java

java入门经典教程 java入门经典教程 java入门经典教程

 // 例2.1.2  RectangleDemo1.java
class Rectangle  // 长方形类
{  
    double length;   
    double width;    
    public double getPerimeter()  // 求周长
{    
        return (length+width)*2;
    }
    public double getArea()  // 求面积
{          
        return length*width;  
    }
}
    public class RectangleDemo1
{
        public static void main(String[] args)
{
double p,a;    // 定义两个double型的变量，用来存放周长和面积
           Rectangle rec1 = new Rectangle();    // 创建一个长方形类的对象
           System.out.println("赋值前");
           System.out.println("Rectangle1 's length:"+rec1.length);
           System.out.println("Rectangle1 's width:"+rec1.width);
           rec1.length = 10;
           rec1.width = 5;
           p = rec1.getPerimeter();
           a = rec1.getArea();
           System.out.println("赋值后");
           System.out.println("Rectangle1 's length:"+rec1.length);
           System.out.println("Rectangle1 's width:"+rec1.width);
           System.out.println("Rectangle1 's perimeter:"+p);
           System.out.println("Rectangle1 's area:"+a);
        }
    }