JAVA类课后练习

1、Pg168--2

package com.hanqi;

import java.util.Scanner;

public class Rectangle {
    
    Rectangle()
    {
        //完成初始化    
         lang=12;
     
         wide=10;    
    }
    
    //属性
    
    double lang;
    
    double wide;
    
    //方法
    void area()
    {
        System.out.println("矩形的面积=" +lang*wide);
    }
    
    public static void main(String[] args)
    {
        Rectangle rec=new Rectangle();
        
        System.out.println("矩形的长度=" +rec.lang);
        
        System.out.println("矩形的宽度=" +rec.wide);
        
        rec.area();
        
    }
}

2.计算机完成加减乘除

package com.hanqi;

import java.util.Scanner;

public class Rectangle {
    
    Rectangle()
    {
        //完成初始化    
         lang=12;
     
         wide=10;    
    }
    
    //属性
    
    double lang;
    
    double wide;
    
    //方法
    void area()
    {
        System.out.println("矩形的面积=" +lang*wide);
    }
    
    public static void main(String[] args)
    {
        Rectangle rec=new Rectangle();
        
        System.out.println("矩形的长度=" +rec.lang);
        
        System.out.println("矩形的宽度=" +rec.wide);
        
        rec.area();
        
    }
}