第十周作业
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 test;
2
3 public class Lwk38 {
4 public static void maopao(int[] x) {
5 for (int i = x.length - 1; i > 0; i--) {
6 for (int j = 0; j < i; j++) {
7 if (x[j] > x[i]) {
8 int a = x[j];
9 x[j] = x[i];
10 x[i] = a;
11 }
12 }
13 }
14 }
15
16 public static void main(String[] args) {
17 int[] x = { 4, 5, 2, 7, 8, 3, 1, 6, 9 };
18 maopao(x);
19 for (int i : x) {
20 System.out.println(i + " ");
21 }
22 }
23 }
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 test;
2
3 import java.util.Scanner;
4
5 public class Lwk39 {
6 public static int jiecheng(int x) {
7 int sum = 1;
8 for (int i = 1; i <= x; i++) {
9 sum *= i;
10 }
11 return sum;
12 }
13
14 public static void main(String[] args) {
15 Scanner input = new Scanner(System.in);
16 System.out.println("请输入n");
17 int n = input.nextInt();
18 System.out.println("n的阶乘为");
19 System.out.println(jiecheng(n));
20 }
21 }
3.编写一个方法，判断该年份是平年还是闰年。[必做题]
1 package test;
2
3 import java.util.Scanner;
4
5 public class Lwk40 {
6 public static void panduan(int y) {
7 if (y % 4 == 0 && y % 100 != 0 || y % 400 == 0) {
8 System.out.println("是闰年");
9 } else {
10 System.out.println("是平年");
11 }
12 }
13
14 public static void main(String[] args) {
15 Scanner input = new Scanner(System.in);
16 System.out.println("请输入年份");
17 int y = input.nextInt();
18 panduan(y);
19 }
20 }
4.课堂没完成的menu菜单，实现幸运抽奖功能
1 package test;
2
3 import java.util.Random;
4 import java.util.Scanner;
5
6 public class Lwk41 {
7 Scanner input = new Scanner(System.in);
8
9 public static void mainMenu() {
10 Scanner input = new Scanner(System.in);
11 System.out.println("欢迎使用本系统");
12 System.out.println("1.登录");
13 System.out.println("2.注册");
14 System.out.println("3.幸运抽奖");
15 System.out.println("4.退出");
16 System.out.println("请选择");
17 int i = input.nextInt();
18 switch (i) {
19 case (1):
20 login();
21 break;
22 case (2):
23 reg();
24 break;
25 case (3):
26 luckly();
27 break;
28
29 }
30 }
31
32 public static void returnMenu() {
33 Scanner input = new Scanner(System.in);
34 System.out.println("是否返回主菜单");
35 if (input.next().equalsIgnoreCase("Y")) {
36 mainMenu();
37 } else {
38 System.out.println("谢谢使用");
39 }
40 }
41
42 private static void login() {
43 Scanner input = new Scanner(System.in);
44 System.out.println("输入用户名");
45 String uname = input.next();
46 System.out.println("输入密码");
47 String upwd = input.next();
48 if (uname.equals("wck") && upwd.equals("1919")) {
49 System.out.println("ok");
50 } else {
51 System.out.println("fail");
52 }
53 returnMenu();
54 }
55
56 private static void reg() {
57 Scanner input = new Scanner(System.in);
58 System.out.println("输入要注册的用户名");
59 String uname = input.next();
60 System.out.println("输入注册密码");
61 String upwd = input.next();
62 System.out.println("再次输入密码");
63 String uppwd = input.next();
64 if (upwd.equals(input()) == uppwd.equals(input())) {
65 System.out.println("注册成功");
66 System.out.println("用户名" + uname + "密码" + upwd);
67 } else {
68 System.out.println("密码错误");
69 }
70 returnMenu();
71 }
72
73 private static Object input() {
74 // TODO Auto-generated method stub
75 return null;
76 }
77
78 private static void luckly() {
79 Scanner input = new Scanner(System.in);
80 Random r = new Random();
81 int luck = r.nextInt(10);
82 System.out.println("输入四位数会员卡号");
83 int id = input.nextInt();
84 if (luck == id) {
85 System.out.println("幸运会员");
86 } else {
87 System.out.println("不是幸运会员");
88 }
89 returnMenu();
90 }
91
92 public static void main(String[] args) {
93 mainMenu();
94
95 }
96 }
