using System;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        IntPtr ptr = new IntPtr(0xff);

​

        Console.WriteLine(ptr.ToString());      // 255

        Console.WriteLine(ptr.ToString("x"));   // ff

​

        Console.WriteLine($"0x{ptr.ToString("x")}"); // 0xff

        Console.WriteLine("0x{0:x}", ptr);

        Console.WriteLine($"0x{ptr:x}"); //0x255        

        Console.WriteLine(IntPtr.Zero is IFormattable);

        Console.WriteLine($"{new MyTest():n}");

        Console.WriteLine($"{new MyTest2():n}");

        Console.WriteLine($"{new MyTest2()}");

        Console.WriteLine($"0x{(int)ptr:x}");

    }

}

​

public class MyTest

{

    public override string ToString()

    {

        return "fluff";

    }

}

​

public class MyTest2 : IFormattable

{

    public override string ToString()

    {

        return "fluff";

    }

    public string ToString(string format)

   {

      return this.ToString(format, CultureInfo.CurrentCulture);

   }

   public string ToString(string format, IFormatProvider provider) 

   {

        if (format == "n")

        {

            return "fluff-modified";

        }

        return this.ToString();

   }

}