第二章：Java语言基础I 第21节课程

练习：如果用户没有输入姓名，则提示“请输入姓名”，否则如果姓名长于10，则提示“姓名长度不大于10”，否则提示“某某某你好”！

- if else if 实现

import java.util.Scanner;

public class Demo
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println("Please input your name: ");
String name = sc.nextLine();

if(name.length() == 0)
{
System.out.println("Please input your name!");
}
else if(name.length() > 10)
{
System.out.println("The length of your name can not be more than 10!");
}
else {
System.out.println("Hello , "+name);
}
}
}

- if return防多级嵌套实现

import java.util.Scanner;

public class Demo
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println("Please input your name: ");
String name = sc.nextLine();

if(name.length() == 0)
{
System.out.println("Please input your name!");
return;
}

if(name.length() > 10)
{
System.out.println("The length of your name can not be more than 10!");
return;
}

System.out.println("Hello , "+name);
}
}