解题思路：直接比较字符的ascii码大小。

import java.util.Scanner;
public class Main {

    public static void main(String[] args) {
    char a,b,c;
    Scanner in=new Scanner(System.in);
    while(in.hasNext()){
     String str=in.nextLine();
     a=str.charAt(0);
     b=str.charAt(1);
     c=str.charAt(2);
     char t;
     if(a<b) 
     {
        t=a;a=b;b=t;
     }
     if(a<c)
     {
         t=a;a=c;c=t;
     }
     if(b<c){
         t=b;b=c;c=t;
     }
     System.out.println(c+" "+b+" "+a);
        }
    in.close();

    }

}