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+---
+language: c#
+filename: csharp-pt.cs
+contributors:
+    - ["Robson Alves", "http://robsonalves.net/"]    
+lang: pt-br
+---
+
+C# é uma linguagem elegante, altamente tipada e orientada a objetos que permite aos desenvolvedores criar uma variedade de aplicações seguras e robustas que são executadas no .NET Framework.
+
+[Leia mais aqui.](http://msdn.microsoft.com/pt-br/library/vstudio/z1zx9t92.aspx)
+
+```c#
+// Comentários de linha única começam com //
+/*
+Comentários de múltiplas linhas são desta forma
+*/
+/// <summary>
+/// Este é um comentário de documentação XML que pode ser usado para gerar documentação
+/// externa ou para fornecer ajuda de contexto dentro de uma IDE
+/// </summary>
+//public void MethodOrClassOrOtherWithParsableHelp() {}
+
+// Especifica os namespaces que o código irá usar
+// Os namespaces a seguir são padrões da biblioteca de classes do .NET Framework
+using System;
+using System.Collections.Generic;
+using System.Dynamic;
+using System.Linq;
+using System.Net;
+using System.Threading.Tasks;
+using System.IO;
+
+// Mas este aqui não é :
+using System.Data.Entity;
+// Para que consiga utilizá-lo, você precisa adicionar novas referências
+// Isso pode ser feito com o gerenciador de pacotes NuGet : `Install-Package EntityFramework`
+
+// Namespaces são escopos definidos para organizar o código em "pacotes" ou "módulos"
+// Usando este código a partir de outro arquivo de origem: using Learning.CSharp;
+namespace Learning.CSharp
+{
+    // Cada .cs deve conter  uma classe com o mesmo nome do arquivo
+    // você está autorizado a contrariar isto, mas evite por sua sanidade.
+    public class AprenderCsharp
+    {
+        // Sintaxe Básica - Pule para as CARACTERÍSTICAS INTERESSANTES se você ja usou Java ou C++ antes.
+        public static void Syntax()
+        {
+            // Use Console.WriteLine para apresentar uma linha
+            Console.WriteLine("Hello World");
+            Console.WriteLine(
+                "Integer: " + 10 +
+                " Double: " + 3.14 +
+                " Boolean: " + true);
+
+            // Para apresentar sem incluir uma nova linha, use Console.Write
+            Console.Write("Hello ");
+            Console.Write("World");
+
+            ///////////////////////////////////////////////////
+            // Tpos e Variáveis
+            //
+            // Declare uma variável usando <tipo> <nome>
+            ///////////////////////////////////////////////////
+
+            // Sbyte - Signed 8-bit integer
+            // (-128 <= sbyte <= 127)
+            sbyte fooSbyte = 100;
+
+            // Byte - Unsigned 8-bit integer
+            // (0 <= byte <= 255)
+            byte fooByte = 100;
+
+            // Short - 16-bit integer
+            // Signed - (-32,768 <= short <= 32,767)
+            // Unsigned - (0 <= ushort <= 65,535)
+            short fooShort = 10000;
+            ushort fooUshort = 10000;
+
+            // Integer - 32-bit integer
+            int fooInt = 1; // (-2,147,483,648 <= int <= 2,147,483,647)
+            uint fooUint = 1; // (0 <= uint <= 4,294,967,295)
+
+            // Long - 64-bit integer
+            long fooLong = 100000L; // (-9,223,372,036,854,775,808 <= long <= 9,223,372,036,854,775,807)
+            ulong fooUlong = 100000L; // (0 <= ulong <= 18,446,744,073,709,551,615)
+            // Numbers default to being int or uint depending on size.
+            // L is used to denote that this variable value is of type long or ulong
+
+            // Double - Double-precision 64-bit IEEE 754 Floating Point
+            double fooDouble = 123.4; // Precision: 15-16 digits
+
+            // Float - Single-precision 32-bit IEEE 754 Floating Point
+            float fooFloat = 234.5f; // Precision: 7 digits
+            // f is used to denote that this variable value is of type float
+
+            // Decimal - a 128-bits data type, with more precision than other floating-point types,
+            // suited for financial and monetary calculations
+            decimal fooDecimal = 150.3m;
+
+            // Boolean - true & false
+            bool fooBoolean = true; // or false
+
+            // Char - A single 16-bit Unicode character
+            char fooChar = 'A';
+
+            // Strings - ao contrário dos anteriores tipos base, que são todos os tipos de valor,
+            // Uma string é um tipo de referência. Ou seja, você pode configurá-lo como nulo
+            string fooString = "\"escape\" quotes and add \n (new lines) and \t (tabs)";
+            Console.WriteLine(fooString);
+
+            //  Você pode acessar todos os caracteres de string com um indexador: 
+            char charFromString = fooString[1]; // => 'e'
+            // Strings são imutáveis: você não pode fazer fooString[1] = 'X';
+
+            // Compare strings com sua atual cultura, ignorando maiúsculas e minúsculas
+            string.Compare(fooString, "x", StringComparison.CurrentCultureIgnoreCase);
+
+            // Formatando, baseado no sprintf
+            string fooFs = string.Format("Check Check, {0} {1}, {0} {1:0.0}", 1, 2);
+
+            // Datas e formatações
+            DateTime fooDate = DateTime.Now;
+            Console.WriteLine(fooDate.ToString("hh:mm, dd MMM yyyy"));
+
+            // Você pode juntar um string em mais de duas linhas com o símbolo @. Para escapar do " use ""
+            string bazString = @"Here's some stuff
+on a new line! ""Wow!"", the masses cried";
+
+            // Use const ou read-only para fazer uma variável imutável
+            // os valores da const são calculados durante o tempo de compilação
+            const int HoursWorkPerWeek = 9001;
+
+            ///////////////////////////////////////////////////
+            // Estrutura de Dados
+            ///////////////////////////////////////////////////
+
+            // Matrizes - zero indexado
+            // O tamanho do array pode ser decidido ainda na declaração
+            // O formato para declarar uma matriz é o seguinte: 
+            // <tipodado>[] <var nome> = new <tipodado>[<array tamanho>];
+            int[] intArray = new int[10];
+
+            // Outra forma de declarar & inicializar uma matriz
+            int[] y = { 9000, 1000, 1337 };
+
+            // Indexando uma matriz - Acessando um elemento
+            Console.WriteLine("intArray @ 0: " + intArray[0]);
+            // Matriz são alteráveis
+            intArray[1] = 1;
+
+            // Listas
+            // Listas são usadas frequentemente tanto quanto matriz por serem mais flexiveis
+            // O formato de declarar uma lista é o seguinte:
+            // List<tipodado> <var nome> = new List<tipodado>();
+            List<int> intList = new List<int>();
+            List<string> stringList = new List<string>();
+            List<int> z = new List<int> { 9000, 1000, 1337 }; // inicializar
+            // O <> são para genéricos - Confira está interessante seção do material
+
+            // Lista não possuem valores padrão.
+            // Um valor deve ser adicionado antes e depois acessado pelo indexador
+            intList.Add(1);
+            Console.WriteLine("intList @ 0: " + intList[0]);
+
+            // Outras estruturas de dados para conferir:
+            // Pilha/Fila
+            // Dicionário (uma implementação de map de hash)
+            // HashSet
+            // Read-only Coleção
+            // Tuple (.Net 4+)
+
+            ///////////////////////////////////////
+            // Operadores
+            ///////////////////////////////////////
+            Console.WriteLine("\n->Operators");
+
+            int i1 = 1, i2 = 2; // Forma curta para declarar diversas variáveis
+
+            // Aritmética é clara
+            Console.WriteLine(i1 + i2 - i1 * 3 / 7); // => 3
+
+            // Modulo
+            Console.WriteLine("11%3 = " + (11 % 3)); // => 2
+
+            // Comparações de operadores
+            Console.WriteLine("3 == 2? " + (3 == 2)); // => falso
+            Console.WriteLine("3 != 2? " + (3 != 2)); // => verdadeiro
+            Console.WriteLine("3 > 2? " + (3 > 2)); // => verdadeiro
+            Console.WriteLine("3 < 2? " + (3 < 2)); // => falso
+            Console.WriteLine("2 <= 2? " + (2 <= 2)); // => verdadeiro
+            Console.WriteLine("2 >= 2? " + (2 >= 2)); // => verdadeiro
+
+            // Operadores bit a bit (bitwise)
+            /*
+            ~       Unário bitwise complemento
+            <<      Signed left shift
+            >>      Signed right shift
+            &       Bitwise AND
+            ^       Bitwise exclusivo OR
+            |       Bitwise inclusivo OR
+            */
+
+            // Incrementações
+            int i = 0;
+            Console.WriteLine("\n->Inc/Dec-rementation");
+            Console.WriteLine(i++); //i = 1. Post-Incrementation
+            Console.WriteLine(++i); //i = 2. Pre-Incrementation
+            Console.WriteLine(i--); //i = 1. Post-Decrementation
+            Console.WriteLine(--i); //i = 0. Pre-Decrementation
+
+            ///////////////////////////////////////
+            // Estrutura de Controle
+            ///////////////////////////////////////
+            Console.WriteLine("\n->Control Structures");
+
+            // Declaração if é como a linguagem C
+            int j = 10;
+            if (j == 10)
+            {
+                Console.WriteLine("I get printed");
+            }
+            else if (j > 10)
+            {
+                Console.WriteLine("I don't");
+            }
+            else
+            {
+                Console.WriteLine("I also don't");
+            }
+
+            // Operador Ternário
+            // Um simples if/else pode ser escrito da seguinte forma
+            // <condição> ? <verdadeiro> : <falso>
+            int toCompare = 17;
+            string isTrue = toCompare == 17 ? "True" : "False";
+
+            // While loop
+            int fooWhile = 0;
+            while (fooWhile < 100)
+            {
+                //Iterated 100 times, fooWhile 0->99
+                fooWhile++;
+            }
+
+            // Do While Loop
+            int fooDoWhile = 0;
+            do
+            {
+                // Inicia a interação 100 vezes, fooDoWhile 0->99
+                if (false)
+                    continue; // pule a intereção atual para apróxima
+
+                fooDoWhile++;
+
+                if (fooDoWhile == 50)
+                    break; // Interrompe o laço inteiro
+
+            } while (fooDoWhile < 100);
+
+            //estrutura de loop for  => for(<declaração para começar>; <condicional>; <passos>)
+            for (int fooFor = 0; fooFor < 10; fooFor++)
+            {
+                //Iterado 10 vezes, fooFor 0->9
+            }
+
+            // For Each Loop
+            // Estrutura do foreach  => foreach(<Tipo Iterador> <Nome do Iterador> in <enumerable>)
+            // O laço foreach  percorre sobre qualquer objeto que implementa IEnumerable ou IEnumerable<T>
+            // Toda a coleção de tipos  (Array, List, Dictionary...) no .Net framework
+            // implementa uma ou mais destas interfaces.
+            // (O ToCharArray() pode ser removido, por que uma string também implementa IEnumerable)
+            foreach (char character in "Hello World".ToCharArray())
+            {
+                //Iterated over all the characters in the string
+            }
+
+            // Switch Case
+            // Um switch funciona com os tipos de dados byte, short, char, e int.
+            // Isto também funcional com tipos enumeradors (discutidos em Tipos Enum),
+            // A classe String, and a few special classes that wrap
+            // tipos primitívos: Character, Byte, Short, and Integer.
+            int month = 3;
+            string monthString;
+            switch (month)
+            {
+                case 1:
+                    monthString = "January";
+                    break;
+                case 2:
+                    monthString = "February";
+                    break;
+                case 3:
+                    monthString = "March";
+                    break;
+                // You can assign more than one case to an action
+                // But you can't add an action without a break before another case
+                // (if you want to do this, you would have to explicitly add a goto case x
+                case 6:
+                case 7:
+                case 8:
+                    monthString = "Summer time!!";
+                    break;
+                default:
+                    monthString = "Some other month";
+                    break;
+            }
+
+            ///////////////////////////////////////
+            // Converting Data Types And Typecasting
+            ///////////////////////////////////////
+
+            // Converting data
+
+            // Convert String To Integer
+            // this will throw a FormatException on failure
+            int.Parse("123");//returns an integer version of "123"
+
+            // try parse will default to type default on failure
+            // in this case: 0
+            int tryInt;
+            if (int.TryParse("123", out tryInt)) // Function is boolean
+                Console.WriteLine(tryInt);       // 123
+
+            // Convert Integer To String
+            // Convert class has a number of methods to facilitate conversions
+            Convert.ToString(123);
+            // or
+            tryInt.ToString();
+
+            // Casting
+            // Cast decimal 15 to a int
+            // and then implicitly cast to long
+            long x = (int) 15M;
+        }
+
+        ///////////////////////////////////////
+        // CLASSES - see definitions at end of file
+        ///////////////////////////////////////
+        public static void Classes()
+        {
+            // See Declaration of objects at end of file
+
+            // Use new to instantiate a class
+            Bicycle trek = new Bicycle();
+
+            // Call object methods
+            trek.SpeedUp(3); // You should always use setter and getter methods
+            trek.Cadence = 100;
+
+            // ToString is a convention to display the value of this Object.
+            Console.WriteLine("trek info: " + trek.Info());
+
+            // Instantiate a new Penny Farthing
+            PennyFarthing funbike = new PennyFarthing(1, 10);
+            Console.WriteLine("funbike info: " + funbike.Info());
+
+            Console.Read();
+        } // End main method
+
+        // CONSOLE ENTRY A console application must have a main method as an entry point
+        public static void Main(string[] args)
+        {
+            OtherInterestingFeatures();
+        }
+
+        //
+        // INTERESTING FEATURES
+        //
+
+        // DEFAULT METHOD SIGNATURES
+
+        public // Visibility
+        static // Allows for direct call on class without object
+        int // Return Type,
+        MethodSignatures(
+            int maxCount, // First variable, expects an int
+            int count = 0, // will default the value to 0 if not passed in
+            int another = 3,
+            params string[] otherParams // captures all other parameters passed to method
+        )
+        {
+            return -1;
+        }
+
+        // Methods can have the same name, as long as the signature is unique
+        // A method that differs only in return type is not unique
+        public static void MethodSignatures(
+            ref int maxCount, // Pass by reference
+            out int count)
+        {
+            count = 15; // out param must be assigned before control leaves the method
+        }
+
+        // GENERICS
+        // The classes for TKey and TValue is specified by the user calling this function.
+        // This method emulates the SetDefault of Python
+        public static TValue SetDefault<TKey, TValue>(
+            IDictionary<TKey, TValue> dictionary,
+            TKey key,
+            TValue defaultItem)
+        {
+            TValue result;
+            if (!dictionary.TryGetValue(key, out result))
+                return dictionary[key] = defaultItem;
+            return result;
+        }
+
+        // You can narrow down the objects that are passed in
+        public static void IterateAndPrint<T>(T toPrint) where T: IEnumerable<int>
+        {
+            // We can iterate, since T is a IEnumerable
+            foreach (var item in toPrint)
+                // Item is an int
+                Console.WriteLine(item.ToString());
+        }
+
+        public static void OtherInterestingFeatures()
+        {
+            // OPTIONAL PARAMETERS
+            MethodSignatures(3, 1, 3, "Some", "Extra", "Strings");
+            MethodSignatures(3, another: 3); // explicity set a parameter, skipping optional ones
+
+            // BY REF AND OUT PARAMETERS
+            int maxCount = 0, count; // ref params must have value
+            MethodSignatures(ref maxCount, out count);
+
+            // EXTENSION METHODS
+            int i = 3;
+            i.Print(); // Defined below
+
+            // NULLABLE TYPES - great for database interaction / return values
+            // any value type (i.e. not a class) can be made nullable by suffixing a ?
+            // <type>? <var name> = <value>
+            int? nullable = null; // short hand for Nullable<int>
+            Console.WriteLine("Nullable variable: " + nullable);
+            bool hasValue = nullable.HasValue; // true if not null
+
+            // ?? is syntactic sugar for specifying default value (coalesce)
+            // in case variable is null
+            int notNullable = nullable ?? 0; // 0
+
+            // IMPLICITLY TYPED VARIABLES - you can let the compiler work out what the type is:
+            var magic = "magic is a string, at compile time, so you still get type safety";
+            // magic = 9; will not work as magic is a string, not an int
+
+            // GENERICS
+            //
+            var phonebook = new Dictionary<string, string>() {
+                {"Sarah", "212 555 5555"} // Add some entries to the phone book
+            };
+
+            // Calling SETDEFAULT defined as a generic above
+            Console.WriteLine(SetDefault<string,string>(phonebook, "Shaun", "No Phone")); // No Phone
+            // nb, you don't need to specify the TKey and TValue since they can be
+            // derived implicitly
+            Console.WriteLine(SetDefault(phonebook, "Sarah", "No Phone")); // 212 555 5555
+
+            // LAMBDA EXPRESSIONS - allow you to write code in line
+            Func<int, int> square = (x) => x * x; // Last T item is the return value
+            Console.WriteLine(square(3)); // 9
+
+            // ERROR HANDLING - coping with an uncertain world
+            try
+            {
+                var funBike = PennyFarthing.CreateWithGears(6);
+
+                // will no longer execute because CreateWithGears throws an exception
+                string some = "";
+                if (true) some = null;
+                some.ToLower(); // throws a NullReferenceException
+            }
+            catch (NotSupportedException)
+            {
+                Console.WriteLine("Not so much fun now!");
+            }
+            catch (Exception ex) // catch all other exceptions
+            {
+                throw new ApplicationException("It hit the fan", ex);
+                // throw; // A rethrow that preserves the callstack
+            }
+            // catch { } // catch-all without capturing the Exception
+            finally
+            {
+                // executes after try or catch
+            }
+
+            // DISPOSABLE RESOURCES MANAGEMENT - let you handle unmanaged resources easily.
+            // Most of objects that access unmanaged resources (file handle, device contexts, etc.)
+            // implement the IDisposable interface. The using statement takes care of
+            // cleaning those IDisposable objects for you.
+            using (StreamWriter writer = new StreamWriter("log.txt"))
+            {
+                writer.WriteLine("Nothing suspicious here");
+                // At the end of scope, resources will be released.
+                // Even if an exception is thrown.
+            }
+
+            // PARALLEL FRAMEWORK
+            // http://blogs.msdn.com/b/csharpfaq/archive/2010/06/01/parallel-programming-in-net-framework-4-getting-started.aspx
+            var websites = new string[] {
+                "http://www.google.com", "http://www.reddit.com",
+                "http://www.shaunmccarthy.com"
+            };
+            var responses = new Dictionary<string, string>();
+
+            // Will spin up separate threads for each request, and join on them
+            // before going to the next step!
+            Parallel.ForEach(websites,
+                new ParallelOptions() {MaxDegreeOfParallelism = 3}, // max of 3 threads
+                website =>
+            {
+                // Do something that takes a long time on the file
+                using (var r = WebRequest.Create(new Uri(website)).GetResponse())
+                {
+                    responses[website] = r.ContentType;
+                }
+            });
+
+            // This won't happen till after all requests have been completed
+            foreach (var key in responses.Keys)
+                Console.WriteLine("{0}:{1}", key, responses[key]);
+
+            // DYNAMIC OBJECTS (great for working with other languages)
+            dynamic student = new ExpandoObject();
+            student.FirstName = "First Name"; // No need to define class first!
+
+            // You can even add methods (returns a string, and takes in a string)
+            student.Introduce = new Func<string, string>(
+                (introduceTo) => string.Format("Hey {0}, this is {1}", student.FirstName, introduceTo));
+            Console.WriteLine(student.Introduce("Beth"));
+
+            // IQUERYABLE<T> - almost all collections implement this, which gives you a lot of
+            // very useful Map / Filter / Reduce style methods
+            var bikes = new List<Bicycle>();
+            bikes.Sort(); // Sorts the array
+            bikes.Sort((b1, b2) => b1.Wheels.CompareTo(b2.Wheels)); // Sorts based on wheels
+            var result = bikes
+                .Where(b => b.Wheels > 3) // Filters - chainable (returns IQueryable of previous type)
+                .Where(b => b.IsBroken && b.HasTassles)
+                .Select(b => b.ToString()); // Map - we only this selects, so result is a IQueryable<string>
+
+            var sum = bikes.Sum(b => b.Wheels); // Reduce - sums all the wheels in the collection
+
+            // Create a list of IMPLICIT objects based on some parameters of the bike
+            var bikeSummaries = bikes.Select(b=>new { Name = b.Name, IsAwesome = !b.IsBroken && b.HasTassles });
+            // Hard to show here, but you get type ahead completion since the compiler can implicitly work
+            // out the types above!
+            foreach (var bikeSummary in bikeSummaries.Where(b => b.IsAwesome))
+                Console.WriteLine(bikeSummary.Name);
+
+            // ASPARALLEL
+            // And this is where things get wicked - combines linq and parallel operations
+            var threeWheelers = bikes.AsParallel().Where(b => b.Wheels == 3).Select(b => b.Name);
+            // this will happen in parallel! Threads will automagically be spun up and the
+            // results divvied amongst them! Amazing for large datasets when you have lots of
+            // cores
+
+            // LINQ - maps a store to IQueryable<T> objects, with delayed execution
+            // e.g. LinqToSql - maps to a database, LinqToXml maps to an xml document
+            var db = new BikeRepository();
+
+            // execution is delayed, which is great when querying a database
+            var filter = db.Bikes.Where(b => b.HasTassles); // no query run
+            if (42 > 6) // You can keep adding filters, even conditionally - great for "advanced search" functionality
+                filter = filter.Where(b => b.IsBroken); // no query run
+
+            var query = filter
+                .OrderBy(b => b.Wheels)
+                .ThenBy(b => b.Name)
+                .Select(b => b.Name); // still no query run
+
+            // Now the query runs, but opens a reader, so only populates are you iterate through
+            foreach (string bike in query)
+                Console.WriteLine(result);
+
+
+
+        }
+
+    } // End LearnCSharp class
+
+    // You can include other classes in a .cs file
+
+    public static class Extensions
+    {
+        // EXTENSION FUNCTIONS
+        public static void Print(this object obj)
+        {
+            Console.WriteLine(obj.ToString());
+        }
+    }
+
+    // Class Declaration Syntax:
+    // <public/private/protected/internal> class <class name>{
+    //    //data fields, constructors, functions all inside.
+    //    //functions are called as methods in Java.
+    // }
+
+    public class Bicycle
+    {
+        // Bicycle's Fields/Variables
+        public int Cadence // Public: Can be accessed from anywhere
+        {
+            get // get - define a method to retrieve the property
+            {
+                return _cadence;
+            }
+            set // set - define a method to set a proprety
+            {
+                _cadence = value; // Value is the value passed in to the setter
+            }
+        }
+        private int _cadence;
+
+        protected virtual int Gear // Protected: Accessible from the class and subclasses
+        {
+            get; // creates an auto property so you don't need a member field
+            set;
+        }
+
+        internal int Wheels // Internal: Accessible from within the assembly
+        {
+            get;
+            private set; // You can set modifiers on the get/set methods
+        }
+
+        int _speed; // Everything is private by default: Only accessible from within this class.
+                    // can also use keyword private
+        public string Name { get; set; }
+
+        // Enum is a value type that consists of a set of named constants
+        // It is really just mapping a name to a value (an int, unless specified otherwise).
+        // The approved types for an enum are byte, sbyte, short, ushort, int, uint, long, or ulong.
+        // An enum can't contain the same value twice.
+        public enum BikeBrand
+        {
+            AIST,
+            BMC,
+            Electra = 42, //you can explicitly set a value to a name
+            Gitane // 43
+        }
+        // We defined this type inside a Bicycle class, so it is a nested type
+        // Code outside of this class should reference this type as Bicycle.Brand
+
+        public BikeBrand Brand; // After declaring an enum type, we can declare the field of this type
+
+        // Decorate an enum with the FlagsAttribute to indicate that multiple values can be switched on
+        [Flags] // Any class derived from Attribute can be used to decorate types, methods, parameters etc
+        public enum BikeAccessories
+        {
+            None = 0,
+            Bell = 1,
+            MudGuards = 2, // need to set the values manually!
+            Racks = 4,
+            Lights = 8,
+            FullPackage = Bell | MudGuards | Racks | Lights
+        }
+
+        // Usage: aBike.Accessories.HasFlag(Bicycle.BikeAccessories.Bell)
+        // Before .NET 4: (aBike.Accessories & Bicycle.BikeAccessories.Bell) == Bicycle.BikeAccessories.Bell
+        public BikeAccessories Accessories { get; set; }
+
+        // Static members belong to the type itself rather then specific object.
+        // You can access them without a reference to any object:
+        // Console.WriteLine("Bicycles created: " + Bicycle.bicyclesCreated);
+        public static int BicyclesCreated { get; set; }
+
+        // readonly values are set at run time
+        // they can only be assigned upon declaration or in a constructor
+        readonly bool _hasCardsInSpokes = false; // read-only private
+
+        // Constructors are a way of creating classes
+        // This is a default constructor
+        public Bicycle()
+        {
+            this.Gear = 1; // you can access members of the object with the keyword this
+            Cadence = 50;  // but you don't always need it
+            _speed = 5;
+            Name = "Bontrager";
+            Brand = BikeBrand.AIST;
+            BicyclesCreated++;
+        }
+
+        // This is a specified constructor (it contains arguments)
+        public Bicycle(int startCadence, int startSpeed, int startGear,
+                       string name, bool hasCardsInSpokes, BikeBrand brand)
+            : base() // calls base first
+        {
+            Gear = startGear;
+            Cadence = startCadence;
+            _speed = startSpeed;
+            Name = name;
+            _hasCardsInSpokes = hasCardsInSpokes;
+            Brand = brand;
+        }
+
+        // Constructors can be chained
+        public Bicycle(int startCadence, int startSpeed, BikeBrand brand) :
+            this(startCadence, startSpeed, 0, "big wheels", true, brand)
+        {
+        }
+
+        // Function Syntax:
+        // <public/private/protected> <return type> <function name>(<args>)
+
+        // classes can implement getters and setters for their fields
+        // or they can implement properties (this is the preferred way in C#)
+
+        // Method parameters can have default values.
+        // In this case, methods can be called with these parameters omitted
+        public void SpeedUp(int increment = 1)
+        {
+            _speed += increment;
+        }
+
+        public void SlowDown(int decrement = 1)
+        {
+            _speed -= decrement;
+        }
+
+        // properties get/set values
+        // when only data needs to be accessed, consider using properties.
+        // properties may have either get or set, or both
+        private bool _hasTassles; // private variable
+        public bool HasTassles // public accessor
+        {
+            get { return _hasTassles; }
+            set { _hasTassles = value; }
+        }
+
+        // You can also define an automatic property in one line
+        // this syntax will create a backing field automatically.
+        // You can set an access modifier on either the getter or the setter (or both)
+        // to restrict its access:
+        public bool IsBroken { get; private set; }
+
+        // Properties can be auto-implemented
+        public int FrameSize
+        {
+            get;
+            // you are able to specify access modifiers for either get or set
+            // this means only Bicycle class can call set on Framesize
+            private set;
+        }
+
+        // It's also possible to define custom Indexers on objects.
+        // All though this is not entirely useful in this example, you
+        // could do bicycle[0] which yields "chris" to get the first passenger or
+        // bicycle[1] = "lisa" to set the passenger. (of this apparent quattrocycle)
+        private string[] passengers = { "chris", "phil", "darren", "regina" };
+
+        public string this[int i]
+        {
+            get {
+                return passengers[i];
+            }
+
+            set {
+                return passengers[i] = value;
+            }
+        }
+
+        //Método para exibir os valores dos atributos deste objeto.
+        public virtual string Info()
+        {
+            return "Gear: " + Gear +
+                    " Cadence: " + Cadence +
+                    " Speed: " + _speed +
+                    " Name: " + Name +
+                    " Cards in Spokes: " + (_hasCardsInSpokes ? "yes" : "no") +
+                    "\n------------------------------\n"
+                    ;
+        }
+
+        // Methods can also be static. It can be useful for helper methods
+        public static bool DidWeCreateEnoughBycles()
+        {
+            // Within a static method, we only can reference static class members
+            return BicyclesCreated > 9000;
+        } // If your class only needs static members, consider marking the class itself as static.
+
+
+    } // end class Bicycle
+
+    // PennyFarthing é uma subclasse de Bicycle
+    class PennyFarthing : Bicycle
+    {
+        // (Penny Farthings são aquelas bicicletas com uma grande roda frontal.
+        // Elas não tem correias.)
+
+        // chamando construtor pai
+        public PennyFarthing(int startCadence, int startSpeed) :
+            base(startCadence, startSpeed, 0, "PennyFarthing", true, BikeBrand.Electra)
+        {
+        }
+
+        protected override int Gear
+        {
+            get
+            {
+                return 0;
+            }
+            set
+            {
+                throw new InvalidOperationException("You can't change gears on a PennyFarthing");
+            }
+        }
+
+        public static PennyFarthing CreateWithGears(int gears)
+        {
+            var penny = new PennyFarthing(1, 1);
+            penny.Gear = gears; // Oops, can't do this!
+            return penny;
+        }
+
+        public override string Info()
+        {
+            string result = "PennyFarthing bicycle ";
+            result += base.ToString(); // Calling the base version of the method
+            return result;
+        }
+    }
+
+    // Interfaces contêm apenas as assinaturas dos membros, sem a implementação.
+    interface IJumpable
+    {
+        void Jump(int meters); // todos os membros da interface são implicitamente públicos
+    }
+
+    interface IBreakable
+    {
+        bool Broken { get; } // interfaces can contain properties as well as methods & events
+    }
+
+    // Class can inherit only one other class, but can implement any amount of interfaces
+    class MountainBike : Bicycle, IJumpable, IBreakable
+    {
+        int damage = 0;
+
+        public void Jump(int meters)
+        {
+            damage += meters;
+        }
+
+        public bool Broken
+        {
+            get
+            {
+                return damage > 100;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Used to connect to DB for LinqToSql example.
+    /// EntityFramework Code First is awesome (similar to Ruby's ActiveRecord, but bidirectional)
+    /// http://msdn.microsoft.com/en-us/data/jj193542.aspx
+    /// </summary>
+    public class BikeRepository : DbContext
+    {
+        public BikeRepository()
+            : base()
+        {
+        }
+
+        public DbSet<Bicycle> Bikes { get; set; }
+    }
+} // End Namespace
+```
+
+## Topics Not Covered
+
+ * Attributes
+ * async/await, yield, pragma directives
+ * Web Development
+ 	* ASP.NET MVC & WebApi (new)
+ 	* ASP.NET Web Forms (old)
+ 	* WebMatrix (tool)
+ * Desktop Development
+ 	* Windows Presentation Foundation (WPF) (new)
+ 	* Winforms (old)
+
+## Further Reading
+
+ * [DotNetPerls](http://www.dotnetperls.com)
+ * [C# in Depth](http://manning.com/skeet2)
+ * [Programming C#](http://shop.oreilly.com/product/0636920024064.do)
+ * [LINQ](http://shop.oreilly.com/product/9780596519254.do)
+ * [MSDN Library](http://msdn.microsoft.com/en-us/library/618ayhy6.aspx)
+ * [ASP.NET MVC Tutorials](http://www.asp.net/mvc/tutorials)
+ * [ASP.NET Web Matrix Tutorials](http://www.asp.net/web-pages/tutorials)
+ * [ASP.NET Web Forms Tutorials](http://www.asp.net/web-forms/tutorials)
+ * [Windows Forms Programming in C#](http://www.amazon.com/Windows-Forms-Programming-Chris-Sells/dp/0321116208)
+ * [C# Coding Conventions](http://msdn.microsoft.com/en-us/library/vstudio/ff926074.aspx)