email

int searchchar(char* str, char chr)
{
    for (int i = 0; str[i] != '\0'; i++)
        if (str[i] == chr) return i;
    return -1;
}

int searchchar(char* str, char chr, int start)
{
    for (int i = start; str[i] != '\0'; i++)
        if (str[i] == chr) return i;

    return -1;
}

int searchcharCount(char* str, char chr)
{
    int count = 0;
    for (int i = 0; str[i] != '\0'; i++)
        if (str[i] == chr) count++;
    return count;
}

int lengthstr(char* str)
{
    int count = 0;
    for (int i = 0; str[i] != '\0'; i++)
        count++;
    return count;
}

bool test_email(char* email)
{
    int total_length = lengthstr(email);

    if (total_length < 8) return false;

    if (searchchar(email, ' ') >= 0) return false;

    int dog_id = searchchar(email, '@');

    if (searchcharCount(email, '@') > 1) return false;

    if (dog_id < 3 || dog_id > total_length - 5) return false;

    int domen_point_id = searchchar(email, '.', dog_id);

    if (domen_point_id > total_length - 3 || domen_point_id < dog_id + 1) return false;

    return true;
}