Add Iterator pattern

src/IteratorPattern/FileExample/LineReader.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace IteratorPattern.FileExample
+{
+    public class LineReader : IEnumerable<string>
+    {
+        public string FilePath { get; private set; }
+        public LineReader(string filePath)
+        {
+            FilePath = filePath;
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
+        public IEnumerator<string> GetEnumerator()
+        {
+            using (TextReader reader = File.OpenText(FilePath))
+            {
+                string line;
+                while ((line = reader.ReadLine()) != null)
+                {
+                    yield return line;
+                }
+            }
+        }
+    }
+    
+}

src/IteratorPattern/FileExample/ReadBigFilesExample.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace IteratorPattern.FileExample
+{
+    public class ReadBigFilesExample
+    {
+        public void Run()
+        {
+            string[] files = Directory.GetFiles("bin/Debug/IteratorPattern/FileExample/SampleFiles");
+            var filesWithContent = from file in files
+                                   where HasAnyLines(file)
+                                   select file;
+
+            foreach (var fileWithContent in filesWithContent)
+            {
+                Console.WriteLine("File with content: {0}", fileWithContent);
+            }
+                        
+        }
+
+        private bool HasAnyLines(string file)
+        {
+            return new LineReader(file).Any();
+        }
+    }
+}