Java第十次作业
1.编写一个方法，实现冒泡排序（由小到大），并调用该方法
1 package sj10; 2 import java.util.Scanner; 3 public class jw { 4 public static void main(String[]args){ 5 Scanner input=new Scanner(System.in); 6 System.out.println("请输入五个数"); 7 int a[]=new int [5]; 8 for (int i = 0; i < a.length; i++) { 9 a[i]=input.nextInt(); 10 11 } for (int i = 0; i < a.length - 1; i++) { 12 for (int j = 0; j < a.length - 1 - i; j++) { 13 if (a[j] > a[j + 1]) { 14 int temp = a[j]; 15 a[j] = a[j + 1]; 16 a[j + 1] = temp; 17 } 18 } 19 } 20 System.out.println("排序后为:"); 21 for (int i = 0; i < a.length; i++) { 22 System.out.println(a[i]); 23 } 24 } 25 }
2.编写一个方法，求整数n的阶乘，例如5的阶乘是1*2*3*4*5。 [必做题]
1 package sj10; 2 import java.util.Scanner; 3 public class sj { 4 5 6 // TODO 自动生成的方法存根 7 public static int jc(int a) { 8 int sum = 1; 9 for (int i = 1; i <= a ; i++) { 10 sum *= i; 11 } 12 System.out.println(+a+"的阶乘是"); 13 return sum; 14 } 15 16 public static void main(String[] args) { 17 System.out.println(jc(5)); 18 } 19 20 }
3.编写一个方法，判断该年份是平年还是闰年。[必做题]
1 package sj10; 2 import java.util.Scanner; 3 public class sj { 4 public static void main(String[] args) { 5 // TODO Auto-generated method stub 6 year(); 7 } 8 public static void year(){ 9 Scanner input=new Scanner(System.in); 10 System.out.println("输入年份"); 11 int year=input.nextInt(); 12 if(year%4==0&&year%100!=0||year%400==0){ 13 System.out.println(year+"是闰年"); 14 }else{ 15 System.out.println(year+"是平年"); 16 } 17 } 18 }
4.课堂没完成的menu菜单，实现幸运抽奖功能
1 package sj10; 2 import java.util.Random; 3 import java.util.Scanner; 4 public class sj { 5 public static void main(String[] args) { 6 mainMenu(); 7 } 8 public static void mainMenu() { 9 Scanner input = new Scanner(System.in); 10 System.out.println("欢迎使用本系统"); 11 System.out.println("1.登录"); 12 System.out.println("2.注册"); 13 System.out.println("3.幸运抽奖"); 14 System.out.println("4.退出"); 15 System.out.println("请选择"); 16 int i = input.nextInt(); 17 switch (i) { 18 case 1: 19 login(); 20 break; 21 case 2: 22 reg(); 23 break; 24 case 3: 25 lucky(); 26 27 } 28 29 } 30 31 public static void lucky() { 32 Scanner input = new Scanner(System.in); 33 System.out.println("输入一个四位数"); 34 Random r = new Random(); 35 int x = r.nextInt(10); 36 int num = input.nextInt(); 37 while (num < 1000 || num > 10000) { 38 System.out.println("输入有误,重新输入"); 39 num = input.nextInt(); 40 if (num >= 1000 && num < 10000) { 41 break; 42 } 43 } 44 int bai = num % 1000 / 100; 45 if (bai == x) { 46 System.out.println("幸运会员"); 47 } else { 48 System.out.println("不是幸运会员"); 49 } 50 51 returnMain(); 52 } 53 54 public static void returnMain() { 55 Scanner input = new Scanner(System.in); 56 System.out.println("是否返回主菜单？"); 57 if (input.next().equalsIgnoreCase("Y")) 58 mainMenu(); 59 else 60 System.out.println("谢谢使用"); 61 } 62 63 public static void reg() { 64 // TODO Auto-generated method stub 65 Scanner input = new Scanner(System.in); 66 System.out.println("输入要注册的用户名"); 67 String uname = input.next(); 68 System.out.println("输入注册密码"); 69 String upwd = input.next(); 70 System.out.println("注册成功"); 71 returnMain(); 72 73 } 74 75 public static void login() { 76 Scanner input = new Scanner(System.in); 77 System.out.println("输入用户名"); 78 String uname = input.next(); 79 System.out.println("输入密码"); 80 String upwd = input.next(); 81 if (uname.equals("ls") && upwd.equals("123")) { 82 System.out.println("ok"); 83 } else { 84 System.out.println("fail"); 85 } 86 returnMain(); 87 } 88 }
