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 text1;
import java.util.Scanner;
public class Homework1{
         public static void maopao() {
             Scanner input = new Scanner(System.in);
             System.out.println("请输入5个数：");
             int x[] = new int[5];
             for (int i = 0; i < x.length; i++) {
                 x[i] = input.nextInt();
             }
             for (int i = 0; i < x.length - 1; i++) {
                 for (int j = 0; j < x.length - 1 - i; j++) {
                     if (x[j] > x[j + 1]) {
                         int temp = x[j];
                         x[j] = x[j + 1];
                         x[j + 1] = temp;
                     }
                 }
             }
             System.out.println("排序后：");
             for (int i = 0; i < x.length; i++) {
                 System.out.println(x[i]);
             }
         }

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

 

 

 

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 text1;
public class Homework1 {
    public static int j(int x) {
        int sum = 1;
        for (int i = 1; i <= x; i++) {
            sum *= i;
        }
        return sum;
    }

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

 

 

 

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package text1;
import java.util.Scanner;
public class Homework1 {
     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("该年份是闰年");
            } else {
                System.out.println("该年份是平年");
            }
        }

        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 text1;
import java.util.Random;
import java.util.Scanner;
public class Homework1{
     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:
                draw();
                break;
            }
        }

        public static void draw() {
            Random r=new Random();
            int a=r.nextInt(10);    
            Scanner input=new Scanner(System.in);
            System.out.println("请输入一个4位会员卡号");
            int n=input.nextInt ();
            int m=n/100%10;
            if(a==m){
                System.out.println("该用户是幸运会员");
            }
            else{
                System.out.println("该用户不是幸运会员"); 
            }
            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();
        }
    }