// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002600/stringbuilder-extractchar

​

// @nuget: Z.ExtensionMethods

​

using System;

using System.Text;

public class Program

{

    public static void Main()

    {

        int endIndex;

​

        // C# Extension Method: StringBuilder - ExtractChar

        Console.WriteLine(new StringBuilder("'a'").ExtractChar());

        Console.WriteLine(new StringBuilder("'\''").ExtractChar());

        Console.WriteLine(new StringBuilder("z'\''").ExtractChar(1, out endIndex));

        Console.WriteLine(endIndex);

​

        try

        {

             Console.WriteLine(new StringBuilder("'").ExtractChar());

        }

        catch (Exception ex)

        {

            Console.WriteLine("Invalid char at position: 0", ex.Message);

        }        

    }

}