第9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
private static void mp() { int a[]={5,6,8,2,3,4,9,1}; for(int i=0;i<a.length-1;i++){ for (int j = 0; j < a.length-i-1; j++) { int max; if (a[j]>a[j+1]) { max=a[j]; a[j]=a[j+1]; a[j+1]=max; } } } for(int i=0;i<a.length;i++){ System.out.println(a[i]); } } public static void main(String[] args) { mp(); } }
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]
public static int jc(int a) { int sum=1; for (int i = 1; i <=a ; i++) { sum*=i; } return sum; } public static void main(String[] args){ Scanner input=new Scanner(System.in); int n=input.nextInt(); System.out.println(jc(n)); }
3.编写一个方法,判断该年份是平年还是闰年。[必做题]
public static void nf(int year){ if (year%4==0&&year%100!=0||year%400==0) { System.out.println("闰年"); } else { System.out.println("平年"); } } public static void main(String[] args) { Scanner input=new Scanner(System.in); nf(input.nextInt()); }
4.课堂没完成的menu菜单,实现幸运抽奖功能
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(); } } 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(); } 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(); System.out.println("幸运数字为"+luck); if (id/100%10==luck) { System.out.println("幸运会员是"+id+"号"); } else { System.out.println("不是幸运会员"); } returnMain(); } public static void main(String[] args) { mainMenu(); }