第十次上机作业

 

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1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

public class home1 {

    
            public static void paixu(int[] a) {
                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 m = 0;
                            a[j] = m;
                            a[j] = a[j + 1];
                            a[j + 1] = m;
                        }
                    }
                }
            }
         
            public static void main(String[] args) {
                // TODO Auto-generated method stub
                int x[] = { 5, 4, 3, 1 };
                paixu(x);
                for (int i : x) {
                    System.out.println(i);
                }
         
            }
         
        
    }

 

 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]

public class home2 {

    
         public static void jc(int a) {
                int b = 1;
                for (int i = 1; i <= a; i++) {
                    b *= i;
         
                }
                System.out.println(b);
            }
         
         public static void main(String[] args) {
            
                int x = 5;
                jc(x);
         
            }
         
    
    }

 

 3.编写一个方法，判断该年份是平年还是闰年。[必做题]

import java.util.Scanner;


public class home3 {

	/**
	 * @param args
	 */
	
		public static void pd(int year) {
	        if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
	            System.out.println(year + "是闰年");
	        } else {
	            System.out.println(year + "是平年");
	        }
	    }
	 
	    public static void main(String[] args) {
	        Scanner input = new Scanner(System.in);
	        System.out.println("输入年份");
	        pd(input.nextInt());
	    }


}

　　

 

 4.课堂没完成的menu菜单，实现幸运抽奖功能

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


public class home4 {

    
         public static void SY() {
                Scanner input = new Scanner(System.in);
                System.out.println("<<<<<<<<<<欢迎使用会员抽奖系统>>>>>>>>>>");
                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("    请输入数字编号进行操作");
                int i = input.nextInt();
                switch (i) {
                case 1:
                    login();
                    break;
                case 2:
                    reg();
                    break;
                case 3:
                    lucky();
                default:
                    System.out.println("输入错误，请重新输入！");
                    SY();
         
                }
         
            }
         
            private static void lucky() {
    
                Scanner input = new Scanner(System.in);
                Random r = new Random();
                int luck = r.nextInt(10);
                System.out.println("请输入四位会员卡号");
                int id = input.nextInt();
                if (luck == id) {
                    System.out.println("恭喜您是幸运会员");
                } else {
                    System.out.println("对不起您不是幸运会员");
                }
                returnMain();
            }
         
            public static void returnMain() {
                Scanner input = new Scanner(System.in);
                System.out.println("是否返回主菜单？（Y/S）");
                if (input.next().equalsIgnoreCase("Y"))
                    SY();
                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("123") && upwd.equals("123")) {
                    System.out.println("输入正确");
                } else {
                    System.out.println("输入错误");
                }
                returnMain();
            }
         
            public static void main(String[] args) {
                SY();
         
            }
    }