char* cipher (int k, char* message)
{
    int i = 0;
    while (char[i] != '.')
    {
       if (char[i] > 96 && char[i] < 123 && char [i] > 63 && char [i] < 91 && char[i] > 47 && char[i] < 58)
        {
            char[i] = char[i] + k;
        }
        i++;
    }
    return message;
}