## 第十次

1.编写一个方法，实现冒泡排序（由小到大），并调用该方法

package TEST;

import java.util.Scanner;

public class Test {
public static void n(int a[]) {
for (int i = 0; i < a.length; i++) {
for (int j =i+1; j < a.length; j++) {
if (a[i]>a[j]) {
int temp=a[i];
a[i]=a[j];
a[j]=temp;
}
}
}

}
public static void main(String[] args) {
int a[]=new int[5];
Scanner b=new Scanner(System.in);
for (int i = 0; i < a.length; i++) {
System.out.println("请输入第"+(i+1)+"个整数");
a[i]=b.nextInt();
}
System.out.println("排序前：");
for (int i = 0; i < a.length; i++) {
System.out.print(a[i]+" ");
}
n(a);
System.out.println();
System.out.println("排序后：");
for (int i = 0; i < a.length; i++) {
System.out.print(a[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 TEST;

import java.util.Scanner;

public class Test {
private static int getSum(int n) {
// TODO Auto-generated method stub
if (n == 1) {
return 1;
}
int temp = getSum(n - 1);
return temp * n;
}

public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input=new Scanner(System.in);
System.out.println("输入一个整数");
int n=input.nextInt();
int sum = getSum(n);
System.out.println("阶乘=" + sum);
}

}

3.编写一个方法，判断该年份是平年还是闰年。[必做题]

package TEST;

import java.util.Scanner;

public class Test {
private static void year() {
Scanner input = new Scanner(System.in);
System.out.println("输入年份");
int a = input.nextInt();
if (a % 4 == 0 && a % 100 != 0 || a % 400 == 0) {
System.out.println("是闰年");
} else {
System.out.println("不是闰年");
}

}

public static void main(String[] args) {
year();
}

}

package TEST;

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

public class Test {
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
Random r=new Random();
int a=r.nextInt(10);
Scanner input=new Scanner(System.in);
System.out.println("输入四位会员卡号");
int kahao= input.nextInt();
System.out.println("幸运数字为"+a);
while (kahao < 1000 || kahao > 10000) {
System.out.println("输入错误,重新输入");
kahao = input.nextInt();
if (kahao >= 1000 && kahao < 10000) {
break;
}
}
int bai=kahao%1000/100;
if (bai == a) {
System.out.println("是幸运会员");
} 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) {
}