好未来：倒置字符串

例子：输入： I like beijing   输出：beijing like i

// next()方法读取到空格就结束；nextLine()读取到回车结束也就是“\r”.import java.util.Scanner;public class Main{    public static void main(String[] args){        Scanner s=new Scanner(System.in);        String str=s.nextLine();        if(str==null)  System.out.println(" ");        String[] string=str.split(" ");        StringBuffer sb=new StringBuffer();        for(int i=string.length-1;i>=0;i--){            if(i!=0){                sb.append(string[i]);                sb.append(" ");            }else{                sb.append(string[i]);            }        }        System.out.println(sb.toString());    }}