22ln

class Calculator{
  static int add(int a, int b) => a + b;  

  static int subtract(int a,int b) => b-a;

  static int multiply(int a,int b)=> a*b;

  static double divide(int a,int b){
    if(b == 0) throw Exception('Cannot divide by zero');
    return a/b;

22ln

//Is the String Odd (return false) or Even (return true)
bool oddOrEven (String txt){
  if(txt.isEmpty){throw Exception('input cannot be empty');}
  RegExp pattern = RegExp(r'^[a-zA-Z]+$');
  if(!pattern.hasMatch(txt)){ throw Exception('input should contain letters a-z or A-z');}
  // if(txt.length %2 == 0) {return true;} return false; , Enhanced to -->
  return txt.length.isEven;
}

//Largest Swap (return true if new number less then input or equal it else false)

22ln

import 'dart:io';

void main(){
  var email = stdin.readLineSync()!;
  //pattern: Starts with letter, number, special characters _ . + % - (not range so put - at the end or at the start ) 
  //      @letters, numbers, . (. to enable multi-level domains)
  //      dot at least 2 letters and stops matching after it
  RegExp emailPattern = RegExp(r'^[\w.+%-]+@[a-zA-Z0-9.]+\.[a-zA-Z]{2,}$');
  print(emailPattern.hasMatch(email));

22ln

import 'dart:io';

void main(){
  //taking the square size from the user
  print("Enter an Integer: ");
  var x = int.parse(stdin.readLineSync()!); 

  Game(x); //calling to the function Game to draw the game board
}

22ln

void main(){
  Map page = {  //three different parts so map

    //Part One
    "header": {

      "top": { //looks different so map
        "title": "Company Logo",
        "nav" : ["Home", "About","Products" , "Contact US"],
      } , 

22ln

//image url:https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOf_9T3L5DzbKhNmNyU95iLlsR573orcbZGQNH9luh1JsQIonMJXTgBZ6d0gF3FIqWzhAW5J4SppoXU6N-yWA80SCrKwM4NqKcw9AwAYYnk8dDS_ovsrKyzS9uM-zTHwfsBH4Nnyuup2YyDbWULlAqmSxHUzZNMmPa5apXghc1z8ECK1CW6cLUai6K/s1200/45b720f598d98b5be44039af1d140f20%20(1).jpg
void main() {
    print ("My cart\n");
    var x = [
        {
            "name": "Polo Shirt For Men",
            "color": "color-Red",
            "price": 30,  
            "quantity": 1,
        },