This is a solution to /r/dailyprogrammer's Intermediate challenge #154, Gorellian Alphabet Sort.

gorellian_alphabet_sort.c

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

#define MAXWORD 80
char alphabet[27];

int gorellian_strcmp(const void *va, const void *vb)
{
	size_t i;
	char *a, *b;

	a = strcpy(malloc(strlen(va)), *(char **) va);
	b = strcpy(malloc(strlen(vb)), *(char **) vb);

	for (i = 0; i < strlen(a); ++i)
		a[i] = strchr(alphabet, a[i] | 32) - alphabet + 1;

	for (i = 0; i < strlen(b); ++i)
		b[i] = strchr(alphabet, b[i] | 32) - alphabet + 1;

	return strcmp(a, b);
}

int main(void)
{
	int i, n;
	char **words;

	scanf("%d", &n);
	scanf("%s", alphabet);

	for (i = 0; i < 26; ++i)
		alphabet[i] |= 32; /* Capitalize the alphabet. */

	words = calloc(n, sizeof(char *));

	for (i = 0; i < n; ++i) {
		words[i] = malloc(MAXWORD);
		scanf("%s ", words[i]);
	}

	qsort(words, n, sizeof(*words), gorellian_strcmp);

	for (i = 0; i < n; ++i)
		printf("%s\n", words[i]);

	return 0;
}