iterator

DesignPatternGuru/DesignPatternGuru.sln

@@ -35,7 +35,9 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "BehavioralPatterns", "Behav
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ChainOfResponsibility", "ChainOfResponsibility\ChainOfResponsibility.csproj", "{9626EF73-1F68-46C8-B7C1-434F02768452}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Command", "Command\Command.csproj", "{629A51B1-04D9-4636-8E21-1712DCFF21DF}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Command", "Command\Command.csproj", "{629A51B1-04D9-4636-8E21-1712DCFF21DF}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Iterator", "Iterator\Iterator.csproj", "{6619433E-476B-404C-94A0-D0C0FE52DE41}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -99,6 +101,10 @@ Global
 		{629A51B1-04D9-4636-8E21-1712DCFF21DF}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{629A51B1-04D9-4636-8E21-1712DCFF21DF}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{629A51B1-04D9-4636-8E21-1712DCFF21DF}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6619433E-476B-404C-94A0-D0C0FE52DE41}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6619433E-476B-404C-94A0-D0C0FE52DE41}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6619433E-476B-404C-94A0-D0C0FE52DE41}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6619433E-476B-404C-94A0-D0C0FE52DE41}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -118,6 +124,7 @@ Global
 		{F0E63700-B550-4D57-B912-18C28B3FEAC6} = {0B9333EC-FB73-4FEE-B600-9ECCD5A356B1}
 		{9626EF73-1F68-46C8-B7C1-434F02768452} = {E3B8A482-1A9A-4B6E-8310-050A44C8E379}
 		{629A51B1-04D9-4636-8E21-1712DCFF21DF} = {E3B8A482-1A9A-4B6E-8310-050A44C8E379}
+		{6619433E-476B-404C-94A0-D0C0FE52DE41} = {E3B8A482-1A9A-4B6E-8310-050A44C8E379}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {3E5A9C6B-2E8A-466E-B5E0-4379902EFFAC}

DesignPatternGuru/Iterator/Collections/WordsCollection.cs

@@ -0,0 +1,37 @@
+using Iterator.Iterators;
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Iterator.Collections
+{
+    internal class WordsCollection : IteratorAggregate
+    {
+        List<string> _collection = new List<string>();
+
+        bool _direction = false;
+
+        public void ReverseDirection()
+        {
+            _direction = !_direction;
+        }
+
+        public List<string> GetItems()
+        {
+            return _collection;
+        }
+
+        public void AddItem(string item)
+        {
+            _collection.Add(item);
+        }
+
+        public override IEnumerator GetEnumerator()
+        {
+            return new AlphabeticalOrderIterator(this, _direction);
+        }
+    }
+}

DesignPatternGuru/Iterator/Iterator.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

DesignPatternGuru/Iterator/Iterators/AlphabeticalOrderIterator.cs

@@ -0,0 +1,54 @@
+using Iterator.Collections;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Iterator.Iterators
+{
+    internal class AlphabeticalOrderIterator : Iterator
+    {
+        private WordsCollection _collection;
+
+        private int _position = -1;
+
+        private bool _reverse = false;
+
+        public AlphabeticalOrderIterator(WordsCollection collection, bool reverse = false)
+        {
+            _collection = collection;
+            _reverse = reverse;
+
+            if (_reverse)
+            {
+                _position = collection.GetItems().Count;
+            }
+        }
+
+        public override object Current()
+        {
+            return _collection.GetItems()[_position];
+        }
+
+        public override int Key()
+        {
+            return _position;
+        }
+
+        public override bool MoveNext()
+        {
+            int updatedPosition = _position + (_reverse ? -1: 1);
+            if (updatedPosition < 0 || updatedPosition >= _collection.GetItems().Count)
+                return false;
+
+            _position = updatedPosition;
+            return true;
+        }
+
+        public override void Reset()
+        {
+            _position = _reverse ? _collection.GetItems().Count - 1 : 0;
+        }
+    }
+}

DesignPatternGuru/Iterator/Iterators/Iterator.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Iterator.Iterators
+{
+    abstract class Iterator : IEnumerator
+    {
+        object IEnumerator.Current => Current();
+
+        public abstract int Key();
+
+        public abstract object Current();
+
+        public abstract bool MoveNext();
+
+        public abstract void Reset();
+    }
+}

DesignPatternGuru/Iterator/Iterators/IteratorAggregate.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Iterator.Iterators
+{
+    abstract class IteratorAggregate : IEnumerable
+    {
+        public abstract IEnumerator GetEnumerator();
+    }
+}

DesignPatternGuru/Iterator/Program.cs

@@ -0,0 +1,30 @@
+using Iterator.Collections;
+
+namespace Iterator
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            WordsCollection collection = new WordsCollection();
+            collection.AddItem("First");
+            collection.AddItem("Second");
+            collection.AddItem("Third");
+
+            Console.WriteLine("Straight traversal: ");
+            foreach (var element in collection)
+            {
+                Console.WriteLine(element);
+            }
+
+            Console.WriteLine();
+
+            Console.WriteLine("Reverse traversal: ");
+            collection.ReverseDirection();
+            foreach (var element in collection)
+            {
+                Console.WriteLine(element);
+            }
+        }
+    }
+}