void string_wipe_whitespaces(char s[]) {
    char *sptr = s; // inizializzo puntatore a s[0]
    char *reader = s;

    while (*reader != '\0') {
        if (*reader != ' ') {
            *sptr = *reader;
            sptr++;
            reader++;
        } else {
            reader++;
        }
    }
    *sptr = '\0';
}