题解 | #字符串反转#

import java.util.Scanner;
public class Main{
    public static void main(String []args){
        Scanner in = new Scanner(System.in);
        /*{
            //方法1：直接调用StringBuilder中的reserve()方法(太过简单)
            //若需要调用此方法，把大括号外面的注释去掉，然后把方法2注释掉便可
            StringBuilder strBui = new StringBuilder(in.nextLine().toLowerCase());
            if(0 < strBui.length() && strBui.length() <= 1000 && strBui != null){
                strBui.reverse();
                System.out.print(strBui);
            }     
        }*/
        {
            //方法2：1-把str字符串倒序转化为char类型的字符，然后通过调用StringBuilder中的append()添加进新的字符串里
            String str = in.next().toLowerCase();
            StringBuilder strBui = new StringBuilder();
            if(0 < str.length() && str.length() <= 1000 && str != null){
                int index = str.length();
                while(index-- > 0){
                    strBui.append(str.charAt(index));
                }
                System.out.print(strBui);
            } 
        }
    }
}