iterator pattern

DesignPattern/Iterator/Client.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Iterator
+{
+    internal class Client
+    {
+        public static void HowToTest()
+        {
+            IAggregate agg = new ColorAggregate();
+            IIterator iter = agg.GetIterator();
+
+            object c1 = iter.Next();
+            object c2 = iter.Next();
+            object c3 = iter.Next();
+
+            Console.WriteLine($"{c1}, {c2}, {c3}");
+        }
+    }
+}

DesignPattern/Iterator/ColorAggregate.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Iterator
+{
+    internal class ColorAggregate : IAggregate
+    {
+        object[] colors = { "White", "Red", "Green", "Blue", "Black" };
+
+        public IIterator GetIterator()
+        {
+            return new CommonIterator(colors);
+        }
+
+        public int Count { get { return colors.Length; } }
+    }
+}

DesignPattern/Iterator/CommonIterator.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Iterator
+{
+    internal class CommonIterator : IIterator
+    {
+        private object[] collection;
+        private int index;
+
+        public CommonIterator(object[] collection)
+        {
+            this.collection = collection;
+            this.index = -1;
+        }
+
+        public bool HasNext { get { return index + 1 < collection.Length; } }
+
+        public object Next()
+        {
+            if (HasNext)
+            {
+                index++;
+                return collection[index];
+            }
+            else
+            {
+                return null;
+            }
+        }
+    }
+}

DesignPattern/Iterator/IAggregate.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Iterator
+{
+    internal interface IAggregate
+    {
+        IIterator GetIterator();
+    }
+}

DesignPattern/Iterator/IIterator.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Iterator
+{
+    internal interface IIterator
+    {
+        bool HasNext { get; }
+        
+        object Next();
+    }
+}

DesignPattern/Iterator/Iterator.csproj

@@ -43,6 +43,11 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Client.cs" />
+    <Compile Include="ColorAggregate.cs" />
+    <Compile Include="CommonIterator.cs" />
+    <Compile Include="IAggregate.cs" />
+    <Compile Include="IIterator.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>

DesignPattern/Iterator/Program.cs

@@ -16,6 +16,9 @@ namespace Iterator
     {
         static void Main(string[] args)
         {
+            Client.HowToTest();
+
+            Console.ReadKey();
         }
     }
 }