/**
 * string-reverse.c - An implemenation of string-reverse.  Designed as
 *   part of a sample solution to assignment 7.
 */

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

#include "string-utils.h"	// For string_reverse


// +---------+--------------------------------------------------------
// | Helpers |
// +---------+

/**
 * Swap elements at positions i and j.
  */
void
char_swap (char *str, int i, int j)
{
  char tmp = str[i];
  str[i] = str[j];
  str[j] = tmp;
} // char_swap


// +--------------------+---------------------------------------------
// | Exported Functions |
// +--------------------+

char *
string_reverse (char *str)
{
  int i;	// Index variable
  int len = strlen (str);
  		// Length, saved for efficiency.
  // For each position from 0 to the middle
  for (i = 0; i < len/2; i++)
    {
      // Swap that element with the element an equivalent distance
      // from the end.
      char_swap (str, i, len - i - 1);
    } // for
  // And we're done
  return str;
} // string_reverse