第十周上机作业
1.编写一个方法,实现冒泡排序(由小到大),并调用该方法
package text; public class java98 { //编写一个方法,实现冒泡排序(由小到大),并调用该方法 public static void paixu(int []a){ for (int i = 0; i < a.length-1; i++) { for (int j = 0; j < a.length-1-i; j++) { if(a[j]>a[j+1]){ int temp=a[j]; a[j]=a[j+1]; a[j+1]=temp; } } } } public static void main(String[] args) { int x[] = {4,9,6,2,5 }; paixu(x); for (int i = 0; i < x.length; i++) { System.out.println(x[i]); } } }
![](https://img2020.cnblogs.com/blog/2318744/202106/2318744-20210610194538944-2132172599.png)
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]
package text; public class java98 { //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] public static int jiecheng(int n){ int sum=1; for (int i = 1; i <=n; i++) { sum*=i; } return sum; } public static void main(String[] args) { System.out.println(jiecheng(5)); } }
3.编写一个方法,判断该年份是平年还是闰年。[必做题]
package text; import java.util.Scanner; public class java98 { public static void year() { Scanner input = new Scanner(System.in); System.out.println("请输入年份"); int year = input.nextInt(); if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) System.out.println(year + "是闰年"); else System.out.println(year + "是平年"); } public static void main(String[] args) { year(); } }
4.课堂没完成的menu菜单,实现幸运抽奖功能
package text; import java.util.Random; import java.util.Scanner; public class java98 { public static void mainMenu(){ Scanner input=new Scanner(System.in); System.out.println("欢迎使用本系统"); System.out.println("1.登录"); System.out.println("2.注册"); System.out.println("3.幸运抽奖"); System.out.println("4.退出"); System.out.println("请选择"); int i=input.nextInt(); switch(i){ case 1: login(); break; case 2: reg(); break; case 3: lucky(); } } private static void lucky() { // 输入四位会员卡号,如果百位数等于随机数,幸运会员。否则不是。同时也要询问是否返回主菜单 Scanner input=new Scanner(System.in); Random r=new Random(); int luck=r.nextInt(10); System.out.println("输入四位数会员卡号"); int id=input.nextInt(); if (luck==id) { System.out.println("幸运会员"); }else{ System.out.println("不是幸运会员"); } returnMain(); } public static void returnMain(){ Scanner input=new Scanner(System.in); System.out.println("是否返回主菜单?"); if(input.next().equalsIgnoreCase("Y")) mainMenu(); else System.out.println("谢谢使用"); } public static void reg() { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("输入要注册的用户名"); String uname=input.next(); System.out.println("输入注册密码"); String upwd=input.next(); System.out.println("注册成功"); returnMain(); } public static void login(){ Scanner input=new Scanner(System.in); System.out.println("输入用户名"); String uname=input.next(); System.out.println("输入密码"); String upwd=input.next(); if(uname.equals("zs")&&upwd.equals("123")){ System.out.println("ok"); }else{ System.out.println("fail"); } returnMain(); } public static void main(String[] args) { mainMenu(); } }