java第十周作业
- 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 public class test { 3 /** 4 * @param args 5 */ 6 public static void main(String[] args) { 7 // TODO Auto-generated method stub 8 int a[]={2,4,6,5,9,8,7}; 9 px(a); 10 for (int i = 0; i < a.length; i++) { 11 System.out.println(a[i]); 12 } 13 } 14 15 private static void px(int[] a) { 16 // TODO Auto-generated method stub 17 for (int i = 0; i < a.length-1; i++) { 18 for (int j = 0; j < a.length-1-i; j++) { 19 if (a[j]>a[j+1]) { 20 int b=a[j]; 21 a[j]=a[j+1]; 22 a[j+1]=b; 23 } 24 } 25 } 26 } 27 28 }
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 public class test1{ 4 5 public static int jiecheng(int n){ 6 int sum=1; 7 for (int i=n; i>0; i--) { 8 sum=sum*i; 9 10 11 } 12 return sum; 13 } 14 public static void main(String[] args) { 15 // TODO Auto-generated method stub 16 System.out.println(jiecheng(5)); 17 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 test; 2 3 import java.util.Scanner; 4 5 public class test2 { 6 public static int year() { 7 System.out.println("输入年份"); 8 Scanner input = new Scanner(System.in); 9 int x = input.nextInt(); 10 if (x % 4 == 0 && x % 100!=0 || x % 400 == 0) { 11 System.out.println("该年为闰年"); 12 }else { 13 System.out.println("该年为平年"); 14 } 15 return x; 16 } 17 public static void main(String[] args) { 18 year(); 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 test3 { 7 8 /** 9 * @param args 10 */ 11 public static void main(String[] args) { 12 mainMenu(); 13 } 14 public static void mainMenu() { 15 Scanner input = new Scanner(System.in); 16 System.out.println("欢迎使用本系统"); 17 System.out.println("1.登录"); 18 System.out.println("2.注册"); 19 System.out.println("3.幸运抽奖"); 20 System.out.println("4.退出"); 21 System.out.println("请选择"); 22 int i = input.nextInt(); 23 switch (i) { 24 case 1: 25 login(); 26 break; 27 case 2: 28 reg(); 29 break; 30 case 3: 31 lucky(); 32 33 } 34 35 } 36 37 public static void lucky() { 38 Scanner input = new Scanner(System.in); 39 System.out.println("输入一个四位数"); 40 Random r = new Random(); 41 int x = r.nextInt(10); 42 int num = input.nextInt(); 43 while (num < 1000 || num > 10000) { 44 System.out.println("输入有误,重新输入"); 45 num = input.nextInt(); 46 if (num >= 1000 && num < 10000) { 47 break; 48 } 49 } 50 int bai = num % 1000 / 100; 51 if (bai == x) { 52 System.out.println("幸运会员"); 53 } else { 54 System.out.println("不是幸运会员"); 55 } 56 57 returnMain(); 58 } 59 60 public static void returnMain() { 61 Scanner input = new Scanner(System.in); 62 System.out.println("是否返回主菜单？"); 63 if (input.next().equalsIgnoreCase("Y")) 64 mainMenu(); 65 else 66 System.out.println("谢谢使用"); 67 } 68 69 public static void reg() { 70 // TODO Auto-generated method stub 71 Scanner input = new Scanner(System.in); 72 System.out.println("输入要注册的用户名"); 73 String uname = input.next(); 74 System.out.println("输入注册密码"); 75 String upwd = input.next(); 76 System.out.println("注册成功"); 77 returnMain(); 78 79 } 80 81 public static void login() { 82 Scanner input = new Scanner(System.in); 83 System.out.println("输入用户名"); 84 String uname = input.next(); 85 System.out.println("输入密码"); 86 String upwd = input.next(); 87 if (uname.equals("ls") && upwd.equals("123")) { 88 System.out.println("ok"); 89 } else { 90 System.out.println("fail"); 91 } 92 returnMain(); 93 } 94 }
