java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

package word;

import java.util.Scanner;

public class test1 {
    public static void main(String[] args){
         Scanner input=new Scanner(System.in);
         System.out.println("请输入五个数");
         int []a=new int [5];
         for(int i=0;i<a.length;i++){
             a[i]= input.nextInt();
         }
        px(a);
         for (int i = 0; i <a.length ; i++) {
            System.out.print(a[i]+" ");
         }
    }

    private static void px(int[] a) {
        // TODO Auto-generated method stub
         for (int i = 0; i < a.length; i++) {
             for(int j=0;j<a.length;j++){
                 if (a[i]<a[j]) {
                 int temp=a[i];
                 a[i]=a[j];
                 a[j]=temp;
                 }
             }
         }
        
    }
}

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 word;

public class test1 {
     public static int jc(int n) {
            int sum = 1;
            for (int i = 1; i <= n; i++) {
                sum *= i;
            }
            System.out.println("阶乘为:");
            return sum;
        }

        public static void main(String[] args) {
            System.out.println(jc(5));
        }
    }

3.编写一个方法，判断该年份是平年还是闰年。

package word;

 import java.util.Scanner;

 public class test1 {
 public static void panduan() {
        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("闰年");
        } else {
            System.out.println("平年");
        }
    }

    public static void main(String[] args) {
        panduan();
    }
}

4.课堂没完成的menu菜单，实现幸运抽奖功能

 package word;

 import java.util.Scanner;

 public class test1 {
     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.退出系统");
            System.out.println("请选择：");
            int i = input.nextInt();
            switch (i) {
            case 1:
                login();
                break;
            case 2:
                register();
                break;
            case 3:
                xycj();
            }
        }

        public static void returnMain() {
            Scanner input = new Scanner(System.in);
            System.out.println("是否返回主菜单？Y/N");
            if (input.next().equalsIgnoreCase("Y"))
                mainMenu();
            else
                System.out.println("谢谢使用");
        }

        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 pwd = input.next();
            if (uname.equals("admin") && pwd.equals("admin"))
                System.out.println("成功");
            else
                System.out.println("失败");
            returnMain();
        }

        public static void register() {
            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 pwd = input.next();
            System.out.println("注册成功");
            returnMain();
        }

        public static void xycj() {
            Scanner input = new Scanner(System.in);
            System.out.println("请输入四位数卡号:");
            int kahao = input.nextInt();
            int random = (int) (Math.random() * 10);
            if (random == kahao / 100 % 10) {
                System.out.println("恭喜你是幸运会员!");
            } else {
                System.out.println("幸运数是:" + random);
                System.out.println("很遗憾你不是幸运会员!");
            }
            returnMain();
        }

        public static void main(String[] args) {
            mainMenu();
        }

    }