simple dictionary using binary search

//strcmp.c

#include <stdio.h>

int my_strcmp(const char[], const char[]);

/*
// testing..
int main(void)
{

    printf("%i\n", strcmp("alpha", "altered"));
    printf("%i\n", strcmp("zioty", "yucca"));

    getchar();
    return 0;
}
*/

int my_strcmp(const char str1[], const char str2[])
{
    int i=0;

    while (str1[i] == str2[i] && str1[i] != '\0' && str2[i] != '\0')
        i++;

    if (str1[i] > str2[i])
        return 1;
    else if (str1[i] < str2[i])
        return -1;
    else
        return 0;
}

// simple dictionary using binary search
// auther mhewedy
// date : 2010-08-13
// compiled under GCC 4.x

#include <stdio.h>
#include <string.h>
#include "strcmp.c"

#define DICT_LENGTH 3

typedef struct _dictionary_s dictionary;
struct _dictionary_s
{
    char word[20];
    char definition[50];
};

int lookup(const char[], const dictionary[], int);
int binary_lookup(const char[], const dictionary[], int, int);

int main(void)
{
    static const dictionary dict[DICT_LENGTH] =
    {
        {"a", "first letter in alphabatic"},
        {"b", "second letter"},
        {"c", "third letter"}
    };
    char word[20];
    int ret=-1;

    do{
        printf("Enter word: \n");
        if (gets(word) == NULL)
            break;
        ret = binary_lookup(word, dict, 0, DICT_LENGTH-1);

        if (ret < 0)
        {
            fprintf(stderr, "word not found!\n");
        }
        else{
            printf("%s : %s\n", word, dict[ret].definition);
        }
        printf("\n");
    }while (1);

    return 0;
}

int binary_lookup(const char word[], const dictionary dict[], int start, int end)
{
    if (start > end)
        return -1;

    int middle = (start+end)/2;
    int cmp = my_strcmp(word, dict[middle].word);

    if (cmp == -1)
    {
        end = middle -1;
        binary_lookup(word, dict, start, end);
    }
    else if (cmp == 1)
    {
        start = middle +1;
        binary_lookup(word, dict, start, end);
    }
    else // 0
    {
        return middle;
    }
}

int lookup(const char word[], const dictionary dict[], int length)
{
    int i;
    for (i=0; i<length; i++)
    {
        if (strcmp(word, dict[i].word) == 0)
            return i;
    }
    return -1;
}