using System;

using System.Linq;

​

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var cities = new Dictionary<string, string>(){

            {"UK", "London, Manchester, Birmingham"},

            {"USA", "Chicago, New York, Washington"},

            {"India", "Mumbai, New Delhi, Pune"}

        };

​

        Console.WriteLine(cities["UK"]); //prints value of UK key

        Console.WriteLine(cities["USA"]);//prints value of USA key

        //Console.WriteLine(cities["France"]); // run-time exception: Key does not exist

​

        //use ContainsKey() to check for an unknown key

        if(cities.ContainsKey("France")){  

            Console.WriteLine(cities["France"]);

        }

​

        //use TryGetValue() to get a value of unknown key

        string result;

​

        if(cities.TryGetValue("France", out result))

        {

            Console.WriteLine(result);

        }

​

        Console.WriteLine("---access elements using for loop---");

        //use ElementAt() to retrieve key-value pair using index

        for (int i = 0; i < cities.Count; i++)

        {

            Console.WriteLine("Key: {0}, Value: {1}", 

                                                    cities.ElementAt(i).Key, 

                                                    cities.ElementAt(i).Value);

        }

    }

}