Generic class and method example in C#, C#

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//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            PrintWhatEver("Hello world");
            PrintWhatEver(2018);
            
            List<string> listString = new List<string>();
            listString.Add("Hello");
            listString.Add("Hellow to");
            listString.Add("Hello for everyone");
            PrintWhatEver(listString);
            
            List<int?> listInt = new List<int?>();
            listInt.Add(1);
            listInt.Add(2);
            listInt.Add(3);
            PrintWhatEver(listInt);
            
            Biodata<string> biodataString = new Biodata<string>();
            Biodata<int?> biodataInt = new Biodata<int?>();
            Biodata<int> biodataIntNotNull = new Biodata<int>();
        }
        
        private static void PrintWhatEver<T>(T thingToPrint)
        {
            if(typeof(T) == typeof(string))
            {
                Console.WriteLine(thingToPrint as string);
            }
            else if(typeof(T) == typeof(int))
            {
                Console.WriteLine((thingToPrint as int?).ToString());
            }
        }
        
        private static void PrintWhatEver<T>(List<T> thingsToPrint)
        {
            if(typeof(T) == typeof(string))
            {
                foreach(string cString in thingsToPrint as List<string>)
                {
                    Console.WriteLine("\n{0}.", cString);
                }
            }
            else if(typeof(T) == typeof(int?))
            {
                foreach(int? cInt in thingsToPrint as List<int?>)
                {
                    Console.WriteLine("\n{0}.",cInt.ToString());
                }
            }
        }
    }
    
    public class Biodata<T>
    {        
        public Biodata()
        {
            if(typeof(T) == typeof(string))
            {
                PrintTypeOfT();
                return;
            }
            else if(typeof(T) == typeof(int?))
            {
                PrintTypeOfT();
                return;
            }
            Console.WriteLine("\ntype of {0} is not controlled in constructor.", typeof(T).ToString());
        }
        
        private void PrintTypeOfT()
        {
            Console.WriteLine("\nIts a {0}.", typeof(T).ToString());
        }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,16 sec, absolute running time: 0,09 sec, cpu time: 0,09 sec, average memory usage: 14 Mb, average nr of threads: 3