"Anagram" guesser using Aspell. Also guesses on substrings, because that's more fun.

anagram.c

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

/* gcc -o anagram anagram.c -O2 -Wall -laspell
*/

void permut(char *chs, char *str, int cur, int len, AspellSpeller * spell_checker) {
	int i;

	if(cur > 0) {
		str[cur] = 0;
		if(aspell_speller_check(spell_checker, str, -1))
			printf("%s\n", str);
//		else
//			printf("%s 0\n", str);
	}

	if(cur == len) {
//		str[cur] = 0;
//		printf("%s\n", str);
		return;
	}

	for(i = cur; i < len; i++) {
		if(strchr(chs + cur, chs[i]) != chs + i) /* skip guessing repeat chars */
			continue;
		/* swap the i-th char of chs to cur, so we move all of our
		 * 'guessed guesses' to <cur in chs */
		char c = chs[i];
		chs[i] = chs[cur];
		chs[cur] = c;

		str[cur] = c;

		permut(chs, str, cur+1, len, spell_checker);

		/* don't forget to swap our guess back! */
		chs[cur] = chs[i];
		chs[i] = c;
	}
}


int main(int argc, char *argv[]) {
	char *chs, *str;
	AspellConfig * spell_config;
	AspellSpeller * spell_checker;
	AspellCanHaveError * possible_err;

	if(argc < 2) {
		exit(1);
	}
	chs = strdup(argv[1]);
	str = malloc(strlen(argv[1]) + 1);

	spell_config = new_aspell_config(); 
	aspell_config_replace(spell_config, "lang", "en_US");
	possible_err = new_aspell_speller(spell_config);
	if (aspell_error_number(possible_err) != 0)
		puts(aspell_error_message(possible_err));
	else
		spell_checker = to_aspell_speller(possible_err);
	
	if(aspell_error_number(possible_err) != 0) {
		puts(aspell_error_message(possible_err));
		exit(1);
	}

	permut(chs, str, 0, strlen(chs), spell_checker);

	return 0;
}