(C#)重写分隔符分割字符串 - string.Split(char[] separator) (New)

修改了以前的同名文章里的方法并且增加了另一个方法实现string.Split(char[] separator)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;
namespace ConsoleApplication2
{
    class Program
    {
        public static string[] MyStringSplit(string input, char[] separator)
        {
            string[] output = null;
            if (input != null && separator != null)
            {
                int num = 1;
                for (int i = 0; i < input.Length; i++)
                {
                    for (int j = 0; j < separator.Length; j++)
                    {
                        if (input[i] == separator[j])
                        {
                            num++;
                            break;
                        }
                    }
                }
                output = new string[num];
                int index = 0;
                bool isSeparator = false;
                for (int i = 0; i < input.Length; i++)
                {
                    for (int j = 0; j < separator.Length; j++)
                    {
                        if (input[i] == separator[j])
                        {
                            index++;
                            isSeparator = true;
                            output[index] = string.Empty;
                            break;
                        }
                        else
                            isSeparator = false;
                    }
                    if (!isSeparator)
                        output[index] += input[i].ToString();
                }
                if (output[0] == null)
                    output[0] = string.Empty;
            }
            return output;
        }

        public static string[] MyStringSplitNew(string input, char[] separator)
        {
            if (input != null && separator != null)
            {
                ArrayList outputList = new ArrayList();
                int index = 0;
                bool isSeparator = false;
                for (int i = 0; i < input.Length; i++)
                {
                    for (int j = 0; j < separator.Length; j++)
                    {
                        if (input[i] == separator[j])
                        {
                            index++;
                            outputList.Add(string.Empty);
                            isSeparator = true;
                            break;
                        }
                        else
                            isSeparator = false;
                    }
                    if (!isSeparator)
                    {
                        if (outputList.Count == index + 1)
                            outputList[index] += input[i].ToString();
                        else
                            outputList.Add(input[i].ToString());
                    }

                }
                return outputList.Cast<string>().ToArray();
            }
            else
                return null;
        }
        static void Main(string[] args)
        {
            //string test = null;
            //string test = string.Empty;
            string test = ".asf.,ad_sf..";
            char[] separators = new char[] { '.', ',', '_', ' ' };
            string[] a;
            a = test.Split(separators);
            PrintArray(a);
            Console.WriteLine("-------------------------------");
            a = MyStringSplit(test, separators);
            PrintArray(a);
            Console.WriteLine("-------------------------------");
            a = MyStringSplitNew(test, separators);
            PrintArray(a);

        }

        public static void PrintArray(string[] input)
        {
            if (input != null && input.Length != 0)
            {
                Console.WriteLine("length: " + input.Length);

                foreach (string item in input)
                {
                    if (item == null)
                        Console.WriteLine("\"null\"");
                    else if (item == string.Empty)
                        Console.WriteLine("\"empty\"");
                    else
                        Console.WriteLine(item);
                }
            }
        }
    }
}