diff --git a/OCP/Device/Laptop.cs b/OCP/Device/Laptop.cs
new file mode 100644
index 0000000..9e659d2
--- /dev/null
+++ b/OCP/Device/Laptop.cs
@@ -0,0 +1,10 @@
+namespace Devices
+{
+    public class Laptop : IDevice
+    {
+        public void DisplayDetails()
+        {
+            Console.WriteLine("Laptop: Model Y, RAM: 16GB, Storage: 512GB");
+        }
+    }
+}
\ No newline at end of file
diff --git a/OCP/Device/SmartPhone.cs b/OCP/Device/SmartPhone.cs
new file mode 100644
index 0000000..e13d0b1
--- /dev/null
+++ b/OCP/Device/SmartPhone.cs
@@ -0,0 +1,10 @@
+namespace Devices
+{
+    public class Smartphone : IDevice
+    {
+        public void DisplayDetails()
+        {
+            Console.WriteLine("Smartphone: Model X, RAM: 8GB, Storage: 128GB");
+        }
+    }
+}
\ No newline at end of file
diff --git a/OCP/DeviceFactoryApp.cs b/OCP/DeviceFactoryApp.cs
new file mode 100644
index 0000000..747fd1e
--- /dev/null
+++ b/OCP/DeviceFactoryApp.cs
@@ -0,0 +1,17 @@
+namespace Devices
+{
+    class DeviceFactoryApp
+    {
+        static void Main()
+        {
+            IDeviceFactory smartphoneFactory = new SmartphoneFactory();
+            IDeviceFactory laptopFactory = new LaptopFactory();
+
+            IDevice smartphone = smartphoneFactory.CreateDevice();
+            IDevice laptop = laptopFactory.CreateDevice();
+
+            smartphone.DisplayDetails();
+            laptop.DisplayDetails();
+        }
+    }
+}
\ No newline at end of file
diff --git a/OCP/Factory/LaptopFactory.cs b/OCP/Factory/LaptopFactory.cs
new file mode 100644
index 0000000..3c185c3
--- /dev/null
+++ b/OCP/Factory/LaptopFactory.cs
@@ -0,0 +1,10 @@
+namespace Devices
+{
+    public class LaptopFactory : IDeviceFactory
+    {
+        public IDevice CreateDevice()
+        {
+            return new Laptop();
+        }
+    }
+}
\ No newline at end of file
diff --git a/OCP/Factory/SmartPhoneFactory.cs b/OCP/Factory/SmartPhoneFactory.cs
new file mode 100644
index 0000000..08d3192
--- /dev/null
+++ b/OCP/Factory/SmartPhoneFactory.cs
@@ -0,0 +1,10 @@
+namespace Devices
+{
+    public class SmartphoneFactory : IDeviceFactory
+    {
+        public IDevice CreateDevice()
+        {
+            return new Smartphone();
+        }
+    }
+}
\ No newline at end of file
diff --git a/OCP/Model/IDevice.cs b/OCP/Model/IDevice.cs
new file mode 100644
index 0000000..42d5cc6
--- /dev/null
+++ b/OCP/Model/IDevice.cs
@@ -0,0 +1,7 @@
+namespace Devices
+{
+    public interface IDevice
+    {
+        void DisplayDetails();
+    }
+}
\ No newline at end of file
diff --git a/OCP/Model/IDeviceFactory.cs b/OCP/Model/IDeviceFactory.cs
new file mode 100644
index 0000000..e480e44
--- /dev/null
+++ b/OCP/Model/IDeviceFactory.cs
@@ -0,0 +1,7 @@
+namespace Devices
+{
+    public interface IDeviceFactory
+    {
+        IDevice CreateDevice();
+    }
+}
\ No newline at end of file
diff --git a/SRP/AreaProcessor.cs b/SRP/AreaProcessor.cs
new file mode 100644
index 0000000..e0cb37f
--- /dev/null
+++ b/SRP/AreaProcessor.cs
@@ -0,0 +1,37 @@
+using System;
+
+public class AreaProcessor
+{
+    private static double _area;
+
+    public static void Main()
+    {
+        Rectangle rectangle = new Rectangle(5.0, 3.0);
+
+        _area = CalculateArea(rectangle);
+        WriteAreaToFile();
+        PrintArea(_area);
+    }
+
+    private static double CalculateArea(Rectangle rectangle)
+    {
+        return rectangle.Length * rectangle.Width;
+    }
+
+    private static void PrintArea(double area)
+    {
+        Console.WriteLine("Area is: " + area);
+    }
+
+    private static void WriteAreaToFile()
+    {
+        try
+        {
+            File.WriteAllText("AreaDetails.txt", _area);
+        }
+        catch (IOException exception)
+        {
+            Console.WriteLine("Error writing to file: " + exception.Message);
+        }
+    }
+}
\ No newline at end of file
diff --git a/SRP/Rectangle.cs b/SRP/Rectangle.cs
new file mode 100644
index 0000000..1a4e410
--- /dev/null
+++ b/SRP/Rectangle.cs
@@ -0,0 +1,11 @@
+public class Rectangle
+{
+    public double Length;
+    public double Width;
+
+    public Rectangle(double length, double width)
+    {
+        Length = length;
+        Width = width;
+    }
+}
\ No newline at end of file