【0729作业】随机生成20个手机号码

需求：随机生成二十个手机号码

 1 package com.random;
 2 
 3 import java.util.Scanner;
 4 
 5 public class Phone {
 6     static Scanner sc = new Scanner(System.in);
 7     public static void getPhoneNum() {
 8         //设置手机号初始前三位
 9         String[] Top3 = {"133", "149", "153", "173", "177",
10                 "180", "181", "189", "199", "130", "131", "132",
11                 "145", "155", "156", "166", "171", "175", "176", "185", "186", "166", "134", "135",
12                 "136", "137", "138", "139", "147", "150", "151", "152", "157", "158", "159", "172",
13                 "178", "182", "183", "184", "187", "188", "198", "170", "171"};
14 
15         //随机出真实号段   使用数组的length属性，获得数组长度，
16         //通过Math.random（）*数组长度获得数组下标，从而随机出前三位的号段
17         String firstNum = Top3[(int) (Math.random() * Top3.length)];
18         //随机出剩下的8位数
19         String lastNum = "";
20         final int last = 8;
21         for (int i = 0; i < last; i++) {
22             //每次循环都从0~9挑选一个随机数
23             lastNum += (int) (Math.random() * 10);
24         }
25         //最终将号段和尾数连接起来
26         String phoneNum = firstNum+ lastNum;
27         System.out.println(phoneNum);
28     }
29     
30 
31     public static  void main(String[] args) {
32         //生成二十个手机号码
33         int num = 20;
34         System.out.println("手机号码如下：");
35         for (int i = 0; i < num; i++) {
36             getPhoneNum();
37         }
38     }
39 }