تحديات برمجيةالتحدي الأول - حل التمرين الرابع بلغة C#

using System;

class Program
{
    static void Main(string[] args)
    {
        Console.Write("Enter any text: ");
        String text = Console.ReadLine();

        Console.Write("Enter word to search occurrences: ");
        String keyword = Console.ReadLine();

        int result = CountOccurrences(text, keyword);

        Console.WriteLine("Total occurrences of '" + keyword + "' is: " + result);
        Console.ReadKey();
    }

    public static int CountOccurrences(String s1, String s2)
    {

        int counter = 0;

        for (int i = 0; i < s1.Length - s2.Length + 1; i++)
        {
            if (s1.Substring(i, s2.Length).Equals(s2))
            {
                counter++;
            }
        }

        return counter;
    }

}