dart language Fundamentals

LearningDart.dart

void main() {
  
  //numbers
   int counter; //null
   double pirce;
  
   int count=4;
   double priceProduct=10.5;
   int? old=int.tryParse("25");
  
  //parsing 
  String stringcount=count.toString();
  print(stringcount);
  
  //string operations
  String name="talel";
  print(name.toUpperCase() +" "+name.toLowerCase());
  print(name.substring(0,4));
  
  bool isAuth=true;
  
  //avec var premier type affecté a variable phone ne peut pas étre changer plus tard
  var phone="29036027";
  //phone=445 //error
  
  //avec dynamic different que var
  dynamic id="user";
  print(id.runtimeType); //string
  id=45;
  print(id.runtimeType);//integer
  
  //constants
  final double textRate=19.5;
  //textRate=20;//error
  
  final List<int> tab=[12,43,45];
  tab.add(20);
  print(tab);// [12, 43, 45, 20]
  
  // const block add
  /*const List<int> tab2=[12,43,45];
  tab2.add(20);
  print(tab2);//Uncaught Error: Unsupported operation: add*/
  
  List<int> numbers=[];
  numbers.add(4);
  numbers.add(5);
  
  //numbers.clear();
  print(numbers.indexOf(13));//-1 si n'exite pas 13 
  print(numbers);
  
  var student=Map();
  student["name"]="talel";
  student["age"]="21";
  print(student.values);
  student.putIfAbsent("hama",()=>"Tekto");
  student.update('age',(int)=>21);
  print(student);
  
  bool ageCorrect=student["age"]==21 ? true : false;
  print(ageCorrect);
  
  for(int i=0;i<numbers.length;i++)
  {
    print(numbers[i]);
  }
  
  for(int val in numbers){
    print(val);
  }
  
  sayHello();
  String messgae=getMessage("mejri");
  print(messgae);
  
  const test=["test1","test2","test3"];
  test.forEach((val){
    print("${test.indexOf(val)}:$val");
  });

}

//simple function

void sayHello(){
  print("hello");
}

String getMessage(String name){
  return "talel ${name}";
}

Future<void> main() async{
  print("first");
  print(await delayResponse());
  print("Five");
}

Future<String> delayResponse() async{
  print("second");
  var future=Future.delayed(Duration(seconds:5),()=>"Third");
  print("fourth");
  return future;
}