static void RecursivePermute(string str, int k)
{
      int i;
      
     if (k == StringLength(str)) {
           printf("%s\n", str);
     }
     else {
            for (i = k; i < StringLength(str); i++) {
                  ExchangeCharacters(str, k, i);
                  RecursivePermute(str, k+1);
                  ExchangeCharacters(str, k, i);
            }
     }
}





static void ExchangeCharacters(string str, int p1, int p2)
{
     char temp;
  
      tmp = str[p1];
      str[p1] = str[p2];
      str[p2] = tmp;
}