CaptchaRecogition.ImageProcess.CalcRate C# (CSharp) Метод

        public static int CalcRate(string t1, string t2)
        {
            if (t1.Length > 0 && t2.Length > 0)
            {
                char[] b1 = t1.ToCharArray();
                char[] b2 = t2.ToCharArray();
                var result = b1.Zip(b2, (b11, b22) => b11 ^ b22).ToArray();
                int cnt = 0;
                for (int i = 0; i < result.Length; i++)
                {
                    int str = result[i];
                    if (str == 0)
                    {
                        cnt++;
                    }
                }
                return cnt * 100 / result.Length;
            }
            else
                return 0;
        }
        /// <summary>