using System;

using System.Collections.Generic;                   

public class Program

{

     public class City

    {

        int population;

        string province;

​

        public int Population{get;set;}

        public string Province{get;set;}

        public string CityName{get;set;}

​

        public City(int population, string province)

        {

            population = Population;

            province = Province;

        }

    }

         public static void Main()

        {

​

            City city1 = new City(5959500, "Ontario");

            //city1.population = 5132794;

            //city1.province = "Ontario"; 

            City city2 = new City(3981800, "Quebec");

            City city3 = new City(1289600, "Alberta");

            City city4 = new City(232100, "Saskatchewan");

            City city5 = new City(357300, "British Columbia");

            City city6 = new City(208400, "New Foundland and Labrador");

            City city7 = new City(140204, "Prince Edward Island");

            City city8 = new City(127900, "New Brunswick");

            City city9 = new City(771200, "Manitoba");

            City city10 = new City(408700, "Nova Scotia");

            City city11 = new City(17000, "Nunavut");

            City city12 = new City(36402, "Yukon");

            City city13 = new City(41462, "Northwest Territories");

            //a lookup dictionary of Canadian provincial capitals, population and province

            Dictionary<string, City> CanadianProvincialCapitals = new Dictionary<string, City>();

            CanadianProvincialCapitals.Add("Toronto", city1);

            CanadianProvincialCapitals.Add("Edmonton", city2);

            CanadianProvincialCapitals.Add("Montreal", city3);

            CanadianProvincialCapitals.Add("Regina", city4);

            CanadianProvincialCapitals.Add("Victoria", city5);

            CanadianProvincialCapitals.Add("St. John's", city6);

            CanadianProvincialCapitals.Add("Charlottetown", city7);

            CanadianProvincialCapitals.Add("Fredericton", city8);

            CanadianProvincialCapitals.Add("Winnipeg", city9);

            CanadianProvincialCapitals.Add("Halifax", city10);

            CanadianProvincialCapitals.Add("Iqaluit", city11);

            CanadianProvincialCapitals.Add("Whitehorse", city12);

            CanadianProvincialCapitals.Add("Yellowknife", city13);

​

            //a set of top 10 North American cities (source: http://en.wikipedia.org/wiki/List_of_cities_in_North_America)

            HashSet<string> top10NorthAmericanCities = new HashSet<string>();

            top10NorthAmericanCities.Add("Mexico City");

            top10NorthAmericanCities.Add("New York City");

            top10NorthAmericanCities.Add("Los Angeles");

            top10NorthAmericanCities.Add("Toronto");

            top10NorthAmericanCities.Add("Chicago");

            top10NorthAmericanCities.Add("Houston");

            top10NorthAmericanCities.Add("Havana");

            top10NorthAmericanCities.Add("Ecatepec de Morelos");

            top10NorthAmericanCities.Add("Montreal");

            top10NorthAmericanCities.Add("Philadelphia");

​

            //use intersectWith() to loop through the set and the dictionary to extract cities appearing in both collections

​

            top10NorthAmericanCities.IntersectWith(CanadianProvincialCapitals.Keys);

            foreach (var city in top10NorthAmericanCities)

            {

                Console.WriteLine("{0} is a provincial capital city in Canada and among top 10 North American Cities", city);

            }

            //Console.ReadKey();

        }

    }

​