/**
 * Nick's favorite sorting routine.
 */

// +---------+-------------------------------------------------------
// | Headers |
// +---------+

#include <string.h>     // strlen, strcmp
#include <stdio.h>      // printf

// +-------+---------------------------------------------------------
// | Types |
// +-------+

/**
 * Procedures that compare two strings for order.  Like strcmp.
 */
typedef int (*Comparator)(char *str1, char *str2);

// +-----------+-----------------------------------------------------
// | Utilities |
// +-----------+

/**
 * Compare to strings by length.
 */
int 
scl (char *str1, char *str2)
{
  return strlen (str1) - strlen (str2);
} // scl

/**
 * Swap two elements in an array.
 */
void
swap (char *strings[], int k, int l)
{
  char *um = strings[k];
  strings[k] = strings[l];
  strings[l] = um;
} // swap 

/**
 * Some strange sorting algorithm that isn't really bubblesort.
 */
int
sort (char *strings[], int len, Comparator compare)
{
  int i, j;
  for (i = 0; i < len; i++)
    {
      for (j = 0; j < len-1; j++)
        {
          if (compare (strings[j], strings[j+1]) > 0)
            {
              swap (strings, j, j+1);
            } // if out of order
        } // for j
    } // for i
  return 1;
} // sort

/**
 * Print an array of strings to stdout.
 */
void
printstrings (char *strings[], int len)
{
  int i;
  if (len == 0)
    {
      printf ("{}");
      return;
    }
  printf ("{\"%s\"", strings[0]);

  for (i = 1; i < len; i++)
    {
      printf (", \"%s\"", strings[i]);
    } // for

  printf ("}");
} // printstrings

// +------+----------------------------------------------------------
// | Main |
// +------+

int
main (int argc, char *argv[])
{
  char **strings = argv+1;
  int len = argc-1;
  printf ("Original array:\t");
  printstrings (strings, len);
  printf ("\n");

  if (!sort (strings, len, scl))
    printf ("Sorting failed!\n");
  printf ("After sorting by len: \t");
  printstrings (strings, len);
  printf ("\n");

  if (!sort (strings, len, (Comparator) strcmp))
    printf ("Sorting failed!\n");
  printf ("After sorting alphabetically: \t");
  printstrings (strings, len);
  printf ("\n");

  return 0;
} // main