AbdullohBahromjonov

const myAge = 15;
const isTeenager = (13 >= 19);
const maryAge = 30;
const bothTeenagers = (myAge == isTeenager) && (maryAge == isTeenager);
const reader = 'Abdulloh';
const ray = 'Ray Wenderlich';
const rayIsReader = (ray == reader);

void main() {
  print(bothTeenagers);

AbdullohBahromjonov

abstract class Person {
  String get name;
  int get age;
  
  void speak(String name, int age);
  void walk() {
    print('walk');
  }
}

AbdullohBahromjonov

class Person {
  final String name;
  final int age;
  
  Person(this.name, this.age);
  
  Person.born() : name = 'Abdulloh', age = 15;
  
  factory Person.zero() {
    final one = Person.born().age-7;

AbdullohBahromjonov

enum Weekdays {
  monday,
  tuesday,
  wednesday,
  thursday,
  friday,
  saturday,
  sunday
}

AbdullohBahromjonov

var number1 = 20;
var number2 = 10;

void main() {
  final plus = number1+number2;
  final minus = number1-number2;
  final multiply = number1*number2;
  final devision = number1/number2;
  final devisionWithReminder = number1~/(number2+2);
  final reminderOfDevision = number1%(number2+2);

AbdullohBahromjonov

void main() {
  //final one = int.parse('one'); //error
  final two = double.parse('2.2'); //successful 
  final three = int.tryParse('one'); //null
  final four = double.tryParse('4.5'); //successful
  final one = int.parse('3');
  
  print('''
$two
$three

AbdullohBahromjonov

String? nullString = 'Abdulloh';

void main() {
  nullString = null;
  
  print (isNullString(nullString));
}

bool isNullString(String? someNullablesString) {
  if (someNullablesString == null) {

AbdullohBahromjonov

int number = 2;
num number2 = 2.0;
double number3 = 3;

String str = 'Abdulloh';

final list = [1, 2, 3];

final map = {1: 'one', 2: 'two', 3: 'three'};
final mapValue = map[1];