第十次上机作业

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 ysc1 {
    public static void mppx() {
         Scanner input=new Scanner(System.in);
         System.out.println("请输入10个数");
         int []a=new int[10];
         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-i-1; j++) {
                 if(a[j]>a[j+1]){
                 int e=a[j];
                 a[j]=a[j+1];
                 a[j+1]=e;
             }
             }
         }
         System.out.println("冒泡排序后");
         for (int i = 0; i < a.length; i++) {
             System.out.println(a[i]);
         }
     }
     public static void main(String[] args) {
         // 1.编写一个方法，实现冒泡排序（由小到大），并调用该方法
         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。 [必做题]

package abc;
 
public class ysc1 {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int sum=getSum(5);
        System.out.println("阶乘="+sum);
    }
 
    private static int getSum(int n) {
        // TODO Auto-generated method stub
        if(n==1){
            return 1;
        }
        int temp=getSum(n-1);
        return temp*n;
          
 
     }
 
  
    }

 

 

 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 ysc1 {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
          Scanner input=new Scanner(System.in);
            System.out.println("请输入一个年份");
            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("该年份不是闰年");
            }
    }
}

 

 

4.课堂没完成的menu菜单，实现幸运抽奖功能

package abc;
import java.util.Scanner;
import java.util.Random;
public class ysc1 {
    public static void mainMenu() {
        // TODO Auto-generated method stub
                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");
                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() {
                Scanner input=new Scanner(System.in);
                Random r=new Random();
                int x=r.nextInt(10);
                System.out.println("幸运数字为"+x);
                System.out.println("请输入四位幸运卡号");
                int number=input.nextInt();
                if (number/100%10==x) {
                    System.out.println("该卡号为幸运卡号");
                }else{
                    System.out.println("该卡不是幸运卡号");
                }
                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 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 reg() {
                Scanner input=new Scanner(System.in);
                System.out.println("请输入要注册的用户名");
                String uname=input.next();
                System.out.println("请输入注册密码");
                String upwd=input.next();
                System.out.println("注册成功");
                returnMain();
            }
 
 
 
            public static void main(String[] args) {
                // TODO Auto-generated method stub
                mainMenu();
 
            }
    }