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 abc;

import java.util.Scanner;

public class Tyu {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
          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();
                 
            } 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;
                    }
                }
            }
            System.out.println("排序后为:");
            for (int i = 0; i < a.length; i++) {
                System.out.println(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 abc;

import java.util.Scanner;

public class Tyu {
      public static int jc(int a) {
          int sum = 1;
          for (int i = 1; i <= a ; i++) {
              sum *= i;
          }
          System.out.println(+a+"的阶乘是");
          return sum;
      }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
           System.out.println(jc(5));
    }

}

 

 

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package abc;

import java.util.Scanner;

public class Tyu {
      public static void prn() {
            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("是闰年");
            } else {
                System.out.println("是平年");
            }
        }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
         prn();
    }

}

 

 

4.课堂没完成的menu菜单，实现幸运抽奖功能

package abc;

import java.util.Scanner;

public class Tyu {
    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:
            hy();
            break;
        }
    }
    //完成3 输入四位会员卡号 如果百位等于随机数，就是幸运会员。询问是否返回主菜单。
    public static void hy(){
        Scanner input = new Scanner(System.in);    
        System.out.println("请输入四位数卡号:");
        int a=input.nextInt();
            int random = (int) (Math.random() * 10);
        if (random == a / 100 % 10){
           System.out.println("幸运会员");
                                                     
        }
        else{
            System.out.println("不是");
            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 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 main(String[] args) {
        mainMenu();
    }

}