anuanu0-0 / dart-fundamentals

Variables

void main() {
  var name = "Anupam";
  print(name);

  String lastName = "Srivastava";
  lastName = "1";
  print(lastName);

  const num1 = 2;
  final num2 = 3;
  print(num1 + num2);

  // Not null
  String? firstName;
  firstName = name;
  print(firstName + " " + lastName);

  late bool isStudying;
  isStudying = false;
  print(isStudying);
  
}

Data types

void main(List<String> args) {
  int i = 10;
  double d = 10.2;
  print(i + d);

  String firstName = "Anupam";
  String lastName = "Srivastava";
  String fullName = "$firstName $lastName";
  print(fullName);

  bool isValidName = true;
  print(isValidName);

  List charList = ['A', 'B', 'C'];
  var numList = [1, 2, 3];

  print(charList);
  print(numList);

  Map nameMap = {"firstName": "Anupam", "lastName":"Srivastava", "age":"2"};
  print(nameMap);
}

Strings

void main(List<String> args) {
  String sum = "${2+2}";
  print(sum); 

  var carName = "  Porshe  ";
  print(carName.length);
  print(carName.isEmpty);
  print(carName);
  print(carName.toLowerCase());
  print(carName.toUpperCase());
  print(carName.trim());
  print(carName.trim().substring(2));

  var path = "http://192.135.2.4:8080";
  print(path.split("."));
}

Numbers

void main(List<String> args) {
  var numStr1 = num.parse('152');
  print(numStr1);

  var numStr2 = num.parse('12.132');
  print(numStr2=='12.132');

  double num1 = 0.01;
  print(num1.isFinite);

  double num2 = 222;
  print(num2.isInfinite);
  print(num2.isNaN);

  num2*=-1;
  print(num2.isNegative);
  print(num2.sign); 
  print(num2.abs());
   
  double num3 = 102.02;
  print(num3.toInt());

  num3 = 102;
  print(num3.toDouble());
  print(num3.toString());

  double num4 = 100.23;
  print(num4.round()); 
}

Functions

void main(List<String> args) {
  printHello('Anu');  
  printHello('MS', extraStr: "DOS");
}

void printHello(var str, {String? extraStr="##"}) {
  print("Hello $str $extraStr");
}

Decision making

import 'dart:io';

void main(List<String> args) {

  print('Enter a number');
    var line = stdin.readLineSync();
    int a = int.parse(line!);
     
    if(a<0){
        print('$a is negative number.');
    } else if(a==0) {
        print('$a is zero. Neither negative nor positive');
    } else {
        print('$a is positive number.');
    }

  var command = 'OPEN';
  switch (command) {
    case 'CLOSED':
      print("executeClosed");
      break;
    case 'PENDING':
      print("executePending");
      break;
    case 'APPROVED':
      print("executeApproved");
      break;
    case 'DENIED':
      print("executeDenied");
      break;
    case 'OPEN':
      print("executeOpen");
      break;
    default:
      print("executeUnknown");
  }
}

Loops

void main(List<String> args) {
  var list1 = ['A', 'B', 'C', 'D'];
  for (var character in list1)
    print(character); 
  
  for (var i = 0; i < 10; i++) {
    print(i);
  }
}

Classes and objects

void main(List<String> args) {
  Vehicle car = new Vehicle("V6");
  SuperCar superCar = new SuperCar("V12");
  car.display();
  superCar.display();
}

class Vehicle {
  String engine;

  Vehicle(this.engine);
  void display() {
    print(engine);
  }
}

class SuperCar extends Vehicle{
  SuperCar(String engine) : super(engine);
}

Maps

void main(List<String> args) {
  var cars = {"Tesla":14, "Toyota":23};
  print(cars);

  var supercars = new Map();
  supercars["porshe"] = 12;
  supercars["mclaren"] = 41;

  print(supercars);
  print(supercars["porshe"]);
}

Lists

void main(List<String> args) {
  var list = ["A", "B", "C"];
  list.add("K");
  print(list);
  print(list.first);
  print(list.last);
  print(list.isEmpty);
  print(list.length);
}

Future

Async-Await

Null safety