using System;

public class Program

{

    public static void Main()

    {

​

            Console.WriteLine("Enter Input String");

            var i_string = Console.ReadLine();

            Console.WriteLine("Enter pattern length: ");

            int p_Length = int.Parse(Console.ReadLine());

            int counter = 0; // to findout number of occurances 

            int totalCount = 0;

            if (i_string.Length < p_Length)

            {

                Console.WriteLine("Input string characters must be greater than search pattern Length");

                Console.ReadLine();

                return;

            }

            for (int a = 0; a<i_string.Length-p_Length; a++) // looping to findout a substring

            {

                var sub_string = i_string.Substring(a, p_Length);

                if (i_string.Contains(sub_string)) 

                {

                    int b = sub_string.Length;

                    int c = i_string.Length;

​

                    for (int i = 0; i <= c - b; i++)

                    {

                        int j;

                        for (j = 0; j < b; j++)  //For current index i, check for pattern match 

                            if (i_string[i + j] != sub_string[j])

                                break;

                        if (j == b) // if there is any matching means patttern found

                        {

                            counter++;

                            totalCount++;

                        }

                    }

                    if (counter > 1)

                        Console.WriteLine("Pattern " + sub_string + " With an occurence value of " + counter);

                    counter = 0;

                }        

            }

            if(totalCount ==0) // if there is no count means no matching 

                Console.WriteLine("No substring with given length" + p_Length + " found");

            Console.ReadLine();

    }

}