using System;

public class Program

{

    public static void Main()

    {

        string s1 = "hi, everyone ,we are working in a c# language, in a new platform";

        char[] array = s1.ToCharArray();

        Console.WriteLine(TextTool.CountStringOccurrences(s1, "a"));

        Console.WriteLine(TextTool.CountStringOccurrences(s1, "in"));

        Console.WriteLine(TextTool.CountStringOccurrences(s1,"language"));

        const char Space = ' ' ;

        const char Comma = ',';

        char[] delimiters = new Char[]

        {

            Space,

            Comma

        };

        string output = "";

        int ctr = 0;

        int i;

        foreach(string subString in s1.Split(delimiters))

        {

            output += ctr++;

            output += ":";

            output += subString;

            output += "\n";

        }

        Console.WriteLine(output);

        for(i=0; i<= array.Length; i++ )

        {

            if(array[i]>=97&& array[i] <=122)

           array[i] = array[i]-32;

        }

        Console.WriteLine("words are:",array);

    }

        //public string UppercaseFirst(string s1)

    //{

        //char[] a = s1.ToCharArray();

        //a[0] = char.ToUpper(a[0]);

        //return new string(a);

            //Console.WriteLine("uppercase letter", a);

    //}

}

​

public static class TextTool

{

    public static int CountStringOccurrences(string text, string pattern)

    {

    int count = 0;

    int i = 0;

    while ((i = text.IndexOf(pattern, i)) != -1)

    {

        i += pattern.Length;

        count++;

    }

    return count;

    }

}

​