练习作业

public class Phone {
private String name;
private double neicun;
double yiyongneicun;
double shengyvneicun;
public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public double getNeicun() {
return neicun;
}

public void setNeicun(double neicun) {
this.neicun = neicun;
}

public double getYiyongneicun() {
return yiyongneicun;
}

public void setYiyongneicun(double yiyongneicun)
{
this.yiyongneicun = yiyongneicun;
}
public void shengyvneicun()
{
neicun-=yiyongneicun;//==>neicun=neicun-yiyongneicun
shengyvneicun=neicun;
//        if(shengyvneicun<0)
//        {
//            System.out.println("您的内存不足");
//        }
//        else if(shengyvneicun==neicun)
//        {
//            System.out.println("您的内存已用完");
//        }
//        else
//        {
System.out.println("剩余内存："+shengyvneicun+"G.");
//        }
}

public Phone(String name, double neicun) {
super();
this.name = name;
this.neicun = neicun;
}

public static void main(String[] args) {
// TODO 自动生成的方法存根

Phone myphone=new Phone("三星",100);
System.out.println("手机品牌是："+myphone.getName());
System.out.println("内存是"+myphone.getNeicun()+"G的。");
myphone.yiyongneicun=2;
System.out.println("手机已用内存;"+myphone.yiyongneicun+"G.");
myphone.shengyvneicun();
//myphone.setYiyongneicun(1);

}
}

作业
手机品牌是：三星
内存是100.0G的。
手机已用内存;2.0G.
剩余内存：98.0G.

解除代码中注释部分，运行出错，跪求老师讲解。

错误输出结果：

手机品牌是：三星
内存是100.0G的。
手机已用内存;2.0G.
您的内存已用完