I've been working on the 2nd Beginners (Help-Free)Programming Challenge of this very same site, and could use some help completing. I have adapted a snippet (by jon guthrie) for a program to permutate a user inputted string.
Thanks for the help. UC

Code:
/*
**  PERMUTE.C - prints all permutations of an input string
**
**  adapted from public domain demo by Jon Guthrie for J. Uslander (4/1/2008).
**
*/

#include    <string.h>
#include    <stdlib.h>
#include    <stdio.h>

int     charcmp(char *, char *);

void    permute(char *, int, int);

char *string;

int     main(void)
{
    printf("Enter a single word string, using only letters and no spaces.\n");
    fgets(string, 15, stdin);
      int length;
      length = strlen(string);
      if (length != 0 && length <=15)
      {      /* It only works if they're printed in order */

      qsort(string, length, 1, (int(*)(const void *, const void *))charcmp);

      permute(string, 0, length);

      return 0;
      }
      else {
          printf("This program only accepts strings of length 1 letter and not more than 14 letters.\n");
          return(0);
}


/*
**  This function prints all of the permutations of string "array"
**  (which has length "len") starting at "start."
*/

void    permute(char *array, int start, int len)
{
      int j;
      char    *s;

      if(start < len)
      {
            if(NULL == (s = malloc(len + 1)))	/* Bug fixed by Stephan Wilms	*/
            {
                  printf("\n\nMemory error!!!\a\a\n");
                  abort();
            }

            strcpy(s, array);
            for(j=start ; j<len ; ++j)
            {
                  int     temp;

                  if((j == start) || (s[j] != s[start]))
                  {     /* For each character that's different    */
                        /* Swap the next first character with...  */
                        /* the current first                      */
                        temp = s[j];
                        s[j] = s[start];
                        s[start] = temp;
                        permute(s, start+1, len);
                  }
            }
            free(s);
      }
      else  puts(array);
}



int charcmp(char *a, char *b)
{
      return(*a - *b);
}
I tried to compile using code::blocks and was told there was an error in the charcmp function.

Thanks again for your help. UC