تحديات برمجيةالتحدي الثاني - حل التمرين الأول بلغة C#

using System;

class Program
{
    public static string RemoveAll(string s1, string s2)
    {

        int L1 = s1.Length;
        int L2 = s2.Length;
        string newS = "";

        for (int i = 0; i < L1;)
        {
            if (i <= L1 - L2 && s1.Substring(i, L2).Equals(s2))
            {
                i += L2;
            }
            else
            {
                newS += s1[i];
                i += 1;
            }
        }
        return newS;
    }

    static void Main(string[] args)
    {
        string text = "I like cats. I have one cat.";
        string keyword = "cat";
        string newText = RemoveAll(text, keyword);

        Console.WriteLine("Before: " + text);
        Console.WriteLine("After:  " + newText);

        Console.ReadKey();
    }

}

Before: I like cats. I have one cat.
After:  I like s. I have one .