Dart tips for better programming about passing arguments between class

Question

Can anyone give me some guidance or tips about better dart programming for my code below? Can it be more simpler? I think it's not good enough, and I also have a question about 'if statement' construction which i added inside the code.

void main() {
  int month = 12;
  int day = 1;
  int year = 2022;
  int newDay;
  int newMonth;
  int newYear;
 
  Calculate calculate = Calculate(day,month,year);
  newDay = calculate.newDay;
   newMonth = calculate.newMonth;
   newYear = calculate.newYear;
  if (newMonth > 7) {
    newYear +=1;}
  print('New date is : $newDay / $newMonth / $newYear');
}

class Calculate{
  int month;
  int day;
  int year;
  
  Calculate(this.day, this.month, this.year);
  get newDay => day + 7;
  get newMonth => month + 1;
  get newYear => year + 1;
  
  
  //QUESTION.. how to construct below 'if statement' within this class?
  //if newMonth > 7 then newYear += 1;
  
}

I make some changes to remove the classes, but i can't return the value, please help how to fix this :

void main() {
  int month = 12;
  int day = 1;
  int year = 2022;
  print(Calculate(day,month,year));

}

Calculate(day,month,year){
  int newday = 0;
  int newmonth = 0 ;
  int newyear = 0;
  newday = day + 7;
  newmonth = month + 1;
  newyear = year + 1;
  List<int> result;

  if (month > 3) {

    return  '$newday/$newmonth/$newyear';}
  else {return  '$newday/$newmonth/$newyear+1';}
    }

Answer 1

Not really understand what you want to do, but here is a little example. You can play with it and change your preferences.

void main() {
  DateData data = DateData(day: 5, month: 12, year: 2022);
  DateData newData = DateData(day: data.day, month: 8, year: 2022)
      .calculateYear()
      .calculateMonth()
      .calculateDay();

  print(data.toString());
  print(newData.toString());
}

class DateData {
  DateData({
    required this.day,
    required this.month,
    required this.year,
  });

  int day;
  int month;
  int year;

  @override
  String toString() => 'DateData(day: $day, month: $month, year: $year)';

  DateData calculateYear() {
    // Do something with `year` value.
    if (month > 7) {
      year += 1;
    }
    return this;
  }

  DateData calculateDay() {
    // Do something with `day` value.
    if (day > 31) {
      day = 1;
    }
    return this;
  }

  DateData calculateMonth() {
    // Do something with `month` value.
    if (month > 12) {
      month = 1;
    }
    return this;
  }
}