/*

DESCRIPTION:

​

Create an extension method to display the number and frequency of number for an array of integers.

​

​

Example array: {1,2,3,4,4,5,5,1,1,1}

​

EXAMPLE OUTPUT:

​

Number 1 appears 4 times  

Number 2 appears 1 times   

Number 3 appears 1 times   

Number 4 appears 2 times   

Number 5 appears 2 times   

*/

using System;

using System.Linq;

using System.Collections.Generic;

​

public static class Program

{

    public static void Main()

    {

        int[] array = {1,2,3,4,4,5,5,1,1,1};                

        //DisplayFrequencyNumber(array);

        array.DisplayFrequencyNumberWithDictionary();

    }

    internal static void DisplayFrequencyNumber(int[] array)

    {

        Console.Write("Display the number and frequency of number from given array: \n"); 

        Console.Write("---------------------------------------------------------------------\n");

        Console.Write("The numbers in the array  are: \n");

        Console.Write(string.Join(",", array) + "\n");  

        var n = from x in array  

                group x by x into y  

                select y;  

        Console.WriteLine("\nThe number and the Frequency are : \n"); 

        foreach (var arrNo in n)  

        {  

            Console.WriteLine("Number " + arrNo.Key + " appears " + arrNo.Count()+" times");  

        }   

    }

    public static void DisplayFrequencyNumberWithDictionary(this int[] array)

    {       

        var dict = new Dictionary<int,int>();

        Console.Write("Display the number and frequency of number from given array: \n"); 

        Console.Write("---------------------------------------------------------------------\n");

        Console.Write("The numbers in the array  are: \n");

        Console.Write(string.Join(",", array) + "\n");  

        foreach (var n in array)  

        {

            if(dict.ContainsKey(n))

            {

                dict[n] += 1;

            }

            else

            {

                dict.Add(n,1);

            }

        }

        Console.WriteLine("\nThe number and the Frequency are : \n"); 

        foreach (var i in dict)  

        {  

            Console.WriteLine($"Number {i.Key} appears {i.Value} times");

        }

    }

}