Java 实现商品批发总金额的显示 关键代码

<span style="font-size:18px;">public class goods {String[] goodss = new String[] { "电风扇", "洗衣机", "电视机", "冰箱", "空调" };double[] qian = new double[] { 124.23, 4500.0, 8800.9, 5000.88, 4456.0 };public boolean denglu() {boolean a = false;Scanner input = new Scanner(System.in);System.out.println("请输入用户名:");String name = input.next();System.out.println("请输入密码:");String mima = input.next();if (name.equals("Tom") && mima.equals("123")) {System.out.println("登陆成功!");a = true;} else {System.out.println("登陆失败!");}return a;}public StringBuffer change(double d) {StringBuffer str = new StringBuffer(String.valueOf(d));for (int i = str.indexOf(".") - 3; i > 0; i = i - 3) {str.insert(i, ',');}return str;}public void showgoods() {System.out.print("*********欢迎进入商品批发城*********");System.out.print("\n\t编号\t商品\t价格\n");for (int i = 0; i < goodss.length; i++) {System.out.print("\t" + (i + 1));System.out.print("\t" + goodss[i]);System.out.print("\t" + change(qian[i]) + "\n");}System.out.println("*************************************************");}***********************Scanner input=new Scanner (System.in);goods w=new goods();int hao,shu;double money=0;if(w.denglu()){w.showgoods();System.out.print("请输入您批发的商品编号：");hao=input.nextInt();System.out.print("请输入批发数量：");shu=input.nextInt();money=w.qian[hao-1]*shu;System.out.print("您需要付款："+w.change(money));}</span>