# 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 ggg;

public class gggg {

public static void main(int x[] ) {
// TODO Auto-generated method stub
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[] = { 6, 5, 9, 2, 4, 1, 49 };
main(x);
for (int i : x) {
System.out.print(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]

package ggg;

public class gggg {

public static void main(String [] args ) {
// TODO Auto-generated method stub
int sum1=jc(5);
int sum2=jc(6);
System.out.println(sum1);
System.out.println(sum2);
}
public static int jc(int n){
int sum=1;
for (int i =1; i <=n; i++) {
sum*=i;
}
return sum;
}
}

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package ggg;

import java.util.Scanner;

public class gggg {

public static void lq(){
// TODO Auto-generated method stub
System.out.println("请输入一个年份");
bc();
}
public static void bc() {
Scanner input=new Scanner(System.in);
int a=input.nextInt();
if(a%4==0||a%400==0&&a%100!=0)
System.out.println("是闰年");
else
System.out.println("不是闰年");
}
public static void main(String[] args){
lq();

}
}

package ggg;

import java.util.Scanner;
import java.util.Random;
public class gggg {

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:
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();
int luck=r.nextInt(10);
System.out.println("输入四位数会员卡号");
int id= input.nextInt();
if (id/100%10==luck) {
System.out.println("幸运会员是"+id+"号");
}
else {
System.out.println("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"))
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();

}

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) {
}