using System;

public class Program

{

    public static void Main()

    {

        var sentence ="I have asked the question in StackOverflow. Therefore i can expect answer here.";

        var searchText="have asked";

        char [] split=new char[]{',',' ','.'};

        var splitSentence=sentence.ToLower().Split(split);

        var splitText=searchText.ToLower().Split(split);

        Console.WriteLine("Search Sentence {0}",splitSentence.Length);

        Console.WriteLine("Search Text {0}",splitText.Length);

        var count=0;

        for(var i=0;i<splitSentence.Length;i++){

            if(splitSentence[i]==splitText[0]){

              var index=i;

                var found=true;

                var j=0;

                for( j=0;j<splitText.Length;j++){

                  if(splitSentence[index++]!=splitText[j])

                  {

                      found=false;

                      break;

                  }

                }

                if(found){

                    Console.WriteLine("Index J {0} ",j);

                    count++;

                    i= index >i ? index-1 : i;

                }

            }

        }

        Console.WriteLine("Total found {0} substring",count);

    }

}