Brainf*ck interpreter, C#

Brainf*ck interpreter

//Title of this code
//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)
        {
            string code = "";
            for (string line = Console.ReadLine(); line != "END"; line = Console.ReadLine())
            {
                int comment = line.IndexOf('#');
                
                if (comment != -1)
                    code += line.Substring(0, comment);
                else
                    code += line;
            }
            new BfInterpreter(code);
        }
    }
    
    public class BfInterpreter
    {
        
        List<byte> array = new List<byte>(new byte[512]);
        
        int dataPtr = 0;
        int instPtr = 0;
        Stack<int> loopStack = new Stack<int>();
        
        string code;
        
        Dictionary<char, Action> instructionMap;
        
        public BfInterpreter(string inCode)
        {
            code = Regex.Replace(inCode, "\\s", "");
            
            instructionMap = new Dictionary<char, Action>
            {
                { '+', Plus },
                { '-', Minus },
                { '>', MoveUp },
                { '<', MoveDown },
                { '.', Output },
                { ',', Input },
                { '[', StartLoop },
                { ']', EndLoop },
            };
            
            for (instPtr = 0; instPtr < code.Length; instPtr++)
            {
                char cmd = code[instPtr];
                
                try {
                    instructionMap[cmd]();
                }
                catch (KeyNotFoundException e)
                {
                    throw new Exception(string.Format("\nUnrecognized input: '{0}'", cmd));
                }
            }
            
            Console.WriteLine("\n");
            for (int i = 0; i < 40; i++) {
                Console.Write(array[i].ToString() + ",");
            }
        }
        
        void Plus()
        {
            array[dataPtr]++;
        }
        
        void Minus()
        {
            array[dataPtr]--;
        }
        
        void MoveUp()
        {
            dataPtr++;
        }
        
        void MoveDown()
        {
            dataPtr--;
        }
        
        void Output()
        {
            char output = (char)array[dataPtr];
            if (char.IsControl(output)) Console.Write("[{0}]", array[dataPtr]);
            else Console.Write(output);
        }
        
        void Input()
        {
            array[dataPtr] = (byte)Console.Read();
        }
        
        void StartLoop()
        {
            if (array[dataPtr] != 0) {
                loopStack.Push(instPtr);
                return;
            }
            
            int nests = 1;
            while (nests > 0)
            {
                if (instPtr == code.Length)
                {
                    throw new Exception("No matching end brace");
                }
                
                int nextBraceIndex = code.IndexOfAny("[]".ToCharArray(), ++instPtr);
                
                if (nextBraceIndex == -1)
                {
                    throw new Exception("No matching end brace");
                }
                
                nests += code[nextBraceIndex] == '[' ? 1 : -1;
                instPtr = nextBraceIndex;
            }
        }
        
        void EndLoop()
        {
            try {
                instPtr = loopStack.Pop() - 1;
            }
            catch (InvalidOperationException e)
            {
                throw new Exception("No matching start brace");
            }
        }
    }
}


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