Configuring RTC time from Serial Port

SetTime.ino

void setTime() {
  // January 21, 2014 at 3am you would call:
  // rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));

  DateTime now = rtc.now();
  int newYear;
  int newMonth;
  int newDay;
  int newHour;
  int newMinute;
  int newSecond;


  Serial.println(" > Enter time (!TddMMyyyyhhmmss)");

  while (! (Serial.available() > 0));
  String time_string = Serial.readString();
  newDay = time_string.substring(2, 4).toInt();
  newMonth = time_string.substring(4, 6).toInt();
  newYear = time_string.substring(6, 10).toInt();
  newHour = time_string.substring(10, 12).toInt();
  newMinute = time_string.substring(12, 14).toInt();
  newSecond = time_string.substring(14, 16).toInt();

  Serial.print(" > New time - ");

  Serial.print(newYear, DEC);
  Serial.print('/');
  Serial.print(newMonth, DEC);
  Serial.print('/');
  Serial.print(newDay, DEC);
  Serial.print(' ');
  Serial.print(newHour, DEC);
  Serial.print(':');
  Serial.print(newMinute, DEC);
  Serial.print(':');
  Serial.print(newSecond, DEC);
  Serial.println();

  Serial.println(" > Change time? (Y/N)");
  while (! (Serial.available() > 0));

  if (Serial.readString() == "Y") {
    rtc.adjust(DateTime(newYear, newMonth, newDay, newHour, newMinute, newSecond));
    Serial.print(" > Time set to ");

    DateTime now = rtc.now();
    Serial.print(now.year(), DEC);
    Serial.print('/');
    Serial.print(now.month(), DEC);
    Serial.print('/');
    Serial.print(now.day(), DEC);
    Serial.print(' ');
    Serial.print(now.hour(), DEC);
    Serial.print(':');
    Serial.print(now.minute(), DEC);
    Serial.print(':');
    Serial.print(now.second(), DEC);
    Serial.println();

    Serial.println("   Sucsesfull!");
  } else {
    Serial.println(" > Canceled");
  }
}