[0729 任务]随机生成 20 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 }