using System;

using System.Collections.Generic;

​

​

public class Program

{

    public static void Main()

    {   

//  if(Contains(CsvColumns[11],":")){

//      Convert.todatetime(csvcolumns[10]).AddDays(-1).ToShortDateString()

//  }else{

//      if(CsvColumns[11]!=""){

//          col=CsvColumns[11]

//      }else{if(CsvColumns[12]!=""){

//          col=CsvColumns[12]

//      }else{if(CsvColumns[13]!=""){

//          col=CsvColumns[13]

//      }else{col=CsvColumns[10]

//      }}};

//  GetDateTime(Convert.ToDateTime(col),"MM/dd/yyyy HH:ss");

        // Parameter: Class Member

        String[] CsvColumns;

        CsvColumns = new string[15];    

        CsvColumns[2] = "ibiabcd";

        CsvColumns[11] = "12/01/2022";

        CsvColumns[12] = "12/12/2022";

        CsvColumns[13] = "12/03/2020 00:01";

        CsvColumns[14] = "12/04/2020 00:01";

        string result;

        if(CsvColumns[12].Contains(":")){

            if(DateTime.TryParse(CsvColumns[11], out DateTime valDate)){ 

                result =  valDate.AddDays(-1).ToString("yyyy-MM-dd HH:mm:ss");

            }else{result = CsvColumns[11];}

        }else{

                if(!String.IsNullOrEmpty(CsvColumns[12])) {result = CsvColumns[12];}

                else if(!String.IsNullOrEmpty(CsvColumns[13])) {result = CsvColumns[13];}

                else if(!String.IsNullOrEmpty(CsvColumns[14])) {result = CsvColumns[14];}

                else {result = CsvColumns[11];}

        };

​

        Console.WriteLine(result); 

    }

}