using System;

namespace StrTest
{
  class Program
  {
    //定義3個字符串 以便測試在多種情況下 下面6種判斷方法的速度
    public static string strTest01 = "";
    public static string strTest02 = string.Empty;
    public static string strTest03 = "0123456789";

    public static DateTime start, end; //定義開始時間 和 結(jié)束時間
    public static TimeSpan ts;    //定義兩個時間的間隔

    //**********************對strTest使用6種測試方法*****************************
    public static void Test(string strTest)
    {
      //string == ""
      start = DateTime.Now;
      for (int counter = 0; counter <= 100000000; counter++)
      {
        if (strTest == "")
        {
        }
      }
      end = DateTime.Now;
      ts = end - start;
      Console.WriteLine("string == /"/" 時間消耗為 " + ts.TotalSeconds + " 秒");

      //string.Equals("")
      start = DateTime.Now;
      for (int counter = 0; counter <= 100000000; counter++)
      {
        if (strTest.Equals(""))
        {
        }
      }
      end = DateTime.Now;
      ts = end - start;
      Console.WriteLine("string.Equals(/"/") 時間消耗為 " + ts.TotalSeconds + " 秒");

      //string == stirng.Empty
      start = DateTime.Now;
      for (int counter = 0; counter <= 100000000; counter++)
      {
        if (strTest == string.Empty)
        {
        }
      }
      end = DateTime.Now;
      ts = end - start;
      Console.WriteLine("string == string.Empty 時間消耗為 " + ts.TotalSeconds + " 秒");

      //string.Equals(string.Empty)
      start = DateTime.Now;
      for (int counter = 0; counter <= 100000000; counter++)
      {
        if (strTest.Equals(string.Empty))
        {
        }
      }
      end = DateTime.Now;
      ts = end - start;
      Console.WriteLine("string.Equals(string.Empty) 時間消耗為 " + ts.TotalSeconds + " 秒");

      //string.Length == 0
      start = DateTime.Now;
      for (int counter = 0; counter <= 100000000; counter++)
      {
        if (strTest.Length == 0)
        {
        }
      }
      end = DateTime.Now;
      ts = end - start;
      Console.WriteLine("string.Length == 0 時間消耗為 " + ts.TotalSeconds + " 秒");

      //string.IsNullOrEmpty(string)
      start = DateTime.Now;
      for (int counter = 0; counter <= 100000000; counter++)
      {
        if (string.IsNullOrEmpty(strTest))
        {
        }
      }
      end = DateTime.Now;
      ts = end - start;
      Console.WriteLine("string.IsNullOrEmpty(string) 時間消耗為 " + ts.TotalSeconds + " 秒" + "/n");
    }

    static void Main(string[] args)
    {
      Console.WriteLine("=======================================");
      Console.WriteLine("strTest = /"/" 的5種測試結(jié)果");     
      Console.WriteLine("=======================================");

      Test(strTest01);

      Console.WriteLine("=======================================");
      Console.WriteLine("strTest = string.Emtpy 的5種測試結(jié)果"); 
      Console.WriteLine("=======================================");

      Test(strTest02);

      Console.WriteLine("=======================================");
      Console.WriteLine("strTest = /"0123456789/" 的5種測試結(jié)果"); 
      Console.WriteLine("=======================================");

      Test(strTest03);

      Console.ReadLine();  //等待鍵盤的輸入 作用:使屏幕暫停在此處
    }
  }
}