倒序字符串

import java.util.Scanner;

public class 倒序字符串 {
public static void main(String[] args)
{

Scanner sc = new Scanner(System.in);
String s = sc.next();
System.out.println(reverse(s));
}

public static String reverse(String str)
{
//长度为空或为1 返回本字符串
if(str == null || str.length() <= 1)
{
return str;
}
//返回最后一个未被递归字符累加上后面已被递归的的字符串
return reverse(str.substring(1)) + str.charAt(0);
}
}