java第十次作业

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

package shi;

public class test1 {

    public static void maopao(int x[] ) {
        int a = 0;
        for (int i = x.length - 1; i > 0; i--) {
            for (int j = 0; j < i; j++) {
                if (x[j] > x[i]) {
                    a = x[j];
                    x[j] = x[i];
                    x[i] = a;
                }

            }

        }

    }

    public static void main(String[] args) {
        int x[] = { 9, 5, 7, 2, 3, 1, 5 };
        maopao(x);
        for (int i : x) {
            System.out.print(i + "\t");
        }
    }
}

 

 

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 shi;

import java.util.Scanner;

public class test1 {

    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);
        System.out.println("输入一个数");
        int jc = jc(input.nextInt());
        System.out.print("阶乘是"+jc);
        }
    }

 

 

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package shi;

import java.util.Scanner;

public class test2 { 
    public static int judge () {
    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("该年份为闰年!");}
    else{
        System.out.println("该年份为平年!");}
    return year;
    }
    
    
    public static void main(String[] args) {
     judge();
 
    }

}

 

 

　　

4.课堂没完成的menu菜单，实现幸运抽奖功能

 

package shi;

import java.util.Random;
import java.util.Scanner;

public class test {
    public static void mainMenu() {
        Scanner input = new Scanner(System.in);
        System.out.println("欢迎使用本系统Random");
        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();
        Scanner input = new Scanner(System.in);
        int luck = r.nextInt(10);
        System.out.println("输入一个4位数会员卡号");
        int id= input.nextInt();
        if (id%10/10 == luck) {
            System.out.println(id+"是幸运会员" );
        } 
        else {
            System.out.println(id+"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();

    }

}