JAVA第十周

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

 

冒泡排序方法

    public void sor(int a[]){
        int mid=0;
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < a.length-1; j++) {
                if(a[j]>a[j+1]) {
                mid=a[j];
                a[j]=a[j+1];
                a[j+1]=mid;
                }
            }
        }
        System.out.println("\n排序成功");
    }

 

运行代码

package text;

public class Run_001 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a[]=new int[] {10,20,90,45,83,34,49,76,66,54};
        System.out.println("排序前");
        for (int i : a) {
            System.out.print(i+" ");
        }
        work10 A=new work10();
        A.sor(a);
        for (int i : a) {
            System.out.print(i+" ");
        }
    }

}

运行截图

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]

阶乘方法

    public int Factorials(int n) {
        int total=1;
        for (int i = 1; i <= n; i++) {
            total=total*i;
        }
        return total;
    }

运行

package text;

public class Run_001 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        work10 A=new work10();
        int a=5;
        System.out.println(a+"的阶乘"+A.Factorials(a));
        
    }

}

截图

 

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

年份方法

    public void year(int y) {
        if(y%4==0&&y%100!=0||y%400==0) {
            System.out.println(y+"是闰年");
        }
        else {
            System.out.println(y+"是平年");
        }
    }

调用运行

package text;

import java.util.Scanner;

public class Run_001 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        work10 A=new work10();
        Scanner input=new Scanner(System.in);
        
        System.out.println("请输入年份");
        int a=input.nextInt();
        A.year(a);
        
    }

}

截图

 

4.课堂没完成的menu菜单，实现幸运抽奖功能

已实现lucky方法功能

package text;

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

public class Luckily_Selection {


        
        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");
            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
            Scanner input=new Scanner(System.in);
            Random r=new Random();
            System.out.println("请输入您的四位会员卡号，与幸运数字相同即为中奖");
            int num=input.nextInt();
            int h=num/100-num/1000*10;
            int r1=r.nextInt(9);
            if(h==r1) {
                System.err.println("恭喜你中奖了！");
            }
            else {
                System.out.println("很遗憾您未能中奖！幸运数字是"+r1);
            }
        }

        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();

        }
        


}

截图