java第10次作

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

package zuoye6;

import java.util.Scanner;



public class zuoye {
public static void mppx(){
    Scanner input = new Scanner(System.in);
     int a[] = new int[3];
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 max=a[j];
            a[j]=a[j+1];
            a[j+1]=max;
        }
    }
}
for (int i = 0; i < a.length; i++) {
    System.out.println(a[i]);
}
}
public static void main(String[] args) {
   mppx();
}

}

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。

package zuoye6;





public class zuoye {
public static  int jc(int n){
    int sum=1;
    for (int i = 1; i <=n; i++) {
        sum=sum*i;
    }
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 zuoye6;

import java.util.Scanner;

public class zuoye {
    
public static  void year(){
 Scanner input  = new Scanner(System.in);
 int year=input.nextInt();
if (( year% 400 == 0) || (year % 4 == 0 && year % 100 != 0)) {
    System.out.println("闰年");
}
else
{
    System.out.println("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 zuoye6;

import java.util.Scanner;

public class zuoye {

    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();
    }

}