creating compare string function

Question

I created a function that compares strings, and as I was frustrated about it always missing the last character in the second string and always returning "identical strings" as a result, I noticed that I was messing around and used gets() instead of fgets() for the second string. I changed that and the function works as expected.

My question is, why does the gets() function subtract that last character? Shouldn't it subtract the null and leave it at that?

Does that mean that as a newcomer to C, I should avoid using gets() and focus on fgets() instead? I'm starting to think of them in the same way I think of strcmp() vs strncmp()

Thanks for your time everyone!

Note: I'm aware that I don't really need the (i==j) at the end, I just left it there (extra security, maybe?).

bool compare_string(const char *string1, const char *string2) {
        int i = 0, j = 0, result = 0;
        while (string1[i] != '\0') {
            i++;
        }

        while (string2[j] != '\0') {
            j++;
        }

        i = 0;
        j = 0;

        while ((string1[i] != '\0') && (string2[j] != '\0')) {
            if (string1[i] < string2[j]) {
                result = -1;
                break;
            } else if (string1[i] > string2[j]) { 
                result = 1;
                break;
            } else if (string1[i] == string2[j]) {
                result = 0;
            }
            i++;
            j++; 
        }

        if ((result == 0) && (i==j)) {
            printf("identical strings \n"); 
        } else if (result == -1) {
            printf("not identical, -1 \n");
        } else if (result == 1) {
            printf("not identical, 1 \n");
        }
}

//in main
char str_compare1[STRING_LIMIT];
    char str_compare2[STRING_LIMIT];

    printf("enter 1st string to compare, (100) characters or less: \n");
    fgets(str_compare1, STRING_LIMIT, stdin);

    printf("enter 2nd string to compare, (100) characters or less \n");
    fgets(str_compare2, STRING_LIMIT, stdin);

    result = compare_string(str_compare1, str_compare2);