JAVA题 矩形

 package com.lo;

 public class juxing {

     private double chang;

     private double kuan;

     public double getChang()
     {
         return chang;
     }
     public double getkuan()
     {
         return kuan;
     }
     public void setChang(double chang)
     {
         if (chang >0)
         {
         this.chang = chang;
         }
         else
         {
             System.out.println("长度值 " + chang + "无效");
         }
         }
     public void setKuan(double kuan)
     {
         if(kuan<=0)
         {
             System.out.println("宽度值 "+ kuan + "无效");
         }
         else
         {
             this.kuan = kuan;
         }
     }
     public juxing()
     {

     }
     public juxing(double chang,double kuan)
     {
         setChang(chang);
         setKuan(kuan);
     }
     public double getMianji()
     {
         return this.chang * this.kuan;
     }
     public static void main(String[]args)
     {
         juxing myJX = new juxing(2,7);

         myJX.chang = 12;

         System.out.println("矩形的面积 = "+myJX.getMianji());
     }
 }

package com.lo;

public class text1 {

public static void main(String[] args) {

juxing myJX1 = new juxing(20,6);

System.out.println("长 = "+myJX1.getChang());

System.out.println("宽 = "+myJX1.getkuan());

System.out.println("矩形面积 ="+myJX1.getMianji());

myJX1.setChang(30);

myJX1.setKuan(15);

System.out.println("矩形面积 ="+myJX1.getMianji());
}
}