递归反转字符串

递归反转字符串

package marslin;import java.util.Scanner;public class 递归反转字符串101 {      public static String reverseString(String x) {          if (x == null || x.length() < 2)              return x;           return reverseString(x.substring(1)) + x.charAt(0); // 填空       }      public static void main(String[] args) {      Scanner s=new Scanner(System.in);        System.out.println(reverseString(s.nextLine()));      }  }