#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
#include <process.h>
#include <time.h>

static const char chars[] = "abcdefghijklmnopqrstuvwxyz";
static const int list_size = sizeof(chars) - 1;
FILE *fp;

void permute(int len)
{
	time_t start, now;
	char *word;
	int *pos;
	int i,j;
	int done = 0;

	start = time(NULL);

	word = calloc(len+1, 1);
	pos = calloc(sizeof(int) * len, 1);
	while(!done)
	{
		for(i = 0; i < len; i++)
		{
			word[i] = chars[pos[i]];
		}

		fprintf(fp, "%s\n", word);

		for(j = len - 1; j >= 0; j--)
		{
			pos[j]++;
			if(pos[j] < list_size)
				break;

			if(j == 0)
				done = 1;

			pos[j] = 0;
		}
	}
	free(word);
	free(pos);

	now = time(NULL);

	printf("Computed all length %i in %lu seconds\n", len, now - start);
}

int min = 1;
int max = 10;

unsigned __stdcall ThreadFunc(void *arg)
{
	int i;
	for(i = min + 1; i <= max; i += 2)
		permute(i);

	return 0;
}

int main()
{
	fp = fopen("list.txt", "wb");

	int i;
	for(i = min; i <= max; i++)
		permute(i);

	fclose(fp);

	return 0;
}