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());
}
}