第八周作业

1:完善menu注册功能,抽奖,看小故事等功能
import java.util.Random;
import java.util.Scanner;

public class menu {
public static void main(String[] args) {
mainMenu();
}

public static void mainMenu() {
Scanner input = new Scanner(System.in);
System.out.println("1.登录");
System.out.println("2.注册");
System.out.println("3.幸运抽奖,输入四位会员卡号,如果百位等于系统随机数,就是星运会员.否则不是.");
System.out.println("4.看小故事,");
System.out.println("5.退出系统");
System.out.println("请选择");
int i = input.nextInt();
switch (i) {
case 1:
login();
break;
case 2:
zhuce();
break;
case 3:
choujiang();
break;
case 4:
sgs();
break;
case 5:
break;

}
}

private static void sgs() {
System.out.println("一个小故事");
returnMain();
}

private static void choujiang() {
Random r=new Random();
int i1 = r.nextInt(10);
System.out.println("请输入四位会员卡号");
Scanner input = new Scanner(System.in);
int i = input.nextInt();
if (i1==i%1000/100){
System.out.println("恭喜你中奖了");
}else {
System.out.println("很遗憾你没有中奖");
}
returnMain();

}

private static void login() {
// TODO Auto-generated method stub
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("登录成功");
} else {
System.out.println("登录失败");
}
returnMain();

}
public static void returnMain(){
System.out.println("是否返回主菜单?Y/N");
Scanner input = new Scanner(System.in);
if (input.next().equalsIgnoreCase("Y")) {
mainMenu();
}else{
System.out.println("谢谢使用");
}

}
public static void zhuce(){
System.out.println("请输入用户名");
Scanner input = new Scanner(System.in);
String line = input.nextLine();
System.out.println("请输入密码");
int i = input.nextInt();
login();

}
}

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 jc {
public static void main(String[] args) {
jc(5);
}
public static void jc(int i){
int jc=1;
for (int j = 1; j <= i; j++) {
jc*=j;
}
System.out.println(i+"的阶乘为"+jc);
}
}

3.编写一个方法，判断该年份是平年还是闰年。[必做题]
public class jc {
public static void main(String[] args) {
pdyj(2020);
}

public static void pdyj(int year){
if (year%4==0&&year%100!=0||(year%400==0)){
System.out.println(year+"年是闰年");
}else {
System.out.println(year+"年不是闰年");
}
}
}