第九次作业(第十周5.7)
1.编写一个方法,实现冒泡排序(由小到大),并调用该方法
package week10; import java.util.Scanner; public class paixu { public static void n(int a[]) { for (int i = 0; i < a.length; i++) { for (int j =i+1; j < a.length; j++) { if (a[i]>a[j]) { int temp=a[i]; a[i]=a[j]; a[j]=temp; } } } } public static void main(String[] args) { int a[]=new int[5]; Scanner b=new Scanner(System.in); System.out.println("请输入5个整数"); for (int i = 0; i < a.length; i++) { a[i]=b.nextInt(); } System.out.println("排序前:"); for (int i = 0; i < a.length; i++) { System.out.print(a[i]+" "); } n(a); System.out.println(); System.out.println("排序后:"); for (int i = 0; i < a.length; i++) { System.out.print(a[i]+" "); } } }
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 week10; public class jiecheng { public static void main(String[] args) { // TODO Auto-generated method stub int sum=getSum(5); System.out.println("阶乘="+sum); } private static int getSum(int n) { // TODO Auto-generated method stub if(n==1){ return 1; } int temp=getSum(n-1); return temp*n; } }
3.编写一个方法,判断该年份是平年还是闰年。[必做题]
package week10; import java.util.Scanner; public class panduan { public static void main(String[] args) { year(); } private static void year() { Scanner input=new Scanner(System.in); System.out.println("输入年份"); int a=input.nextInt(); if (a%4==0&&a%100!=0||a%400==0) { System.out.println("是闰年"); } else { System.out.println("不是闰年"); } } }
4.课堂没完成的menu菜单,实现幸运抽奖功能
package week10; import java.util.Random; import java.util.Scanner; public class Menu { 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 Random r=new Random(); int a=r.nextInt(10); System.out.println("("+a+")"); Scanner input=new Scanner(System.in); System.out.println("输入四位会员卡号"); int kahao= input.nextInt(); while (kahao < 1000 || kahao > 10000) { System.out.println("输入错误,重新输入"); kahao = input.nextInt(); if (kahao >= 1000 && kahao < 10000) { break; } } int bai=kahao%1000/100; if (bai == a) { System.out.println("是幸运会员"); } 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(); } }