小编BDo*_*Doe的帖子

简单的程序将数字输出到电话号码格式我似乎无法退出循环我不知道我做错了什么我想!PhoneNumber.equals("999"); 当用户输入999时它将退出循环,但它不起作用.任何人都可以帮我这里是我的代码

import javax.swing.*;

public class PhoneNumberFormat 
{

    public static void main(String[] args) 
    {
      String PhoneNumber;
      int numLength= 10;

      do
      {

          PhoneNumber = JOptionPane.showInputDialog(null, 
                 "Enter your 10 digit phone number or enter 999 to quit");
          while(PhoneNumber.length() != numLength)
          {
              PhoneNumber = JOptionPane.showInputDialog(null,
                  "Error: You Entered " + PhoneNumber.length() + " digits\nPlease"
                      + " Enter a 10 digit Phone number");    
          }

            StringBuilder str = new StringBuilder (PhoneNumber);
            str.insert(0, '(');
            str.insert(4, ')');
            str.insert(5,' ');
            str.insert(9, '-');

        JOptionPane.showMessageDialog(null, "Your telephone number is " …