diff --git a/Program.cs b/Program.cs
new file mode 100644
index 0000000..d31bb61
--- /dev/null
+++ b/Program.cs
@@ -0,0 +1,13 @@
+using StringProcessingApp.Views;
+
+namespace StringProcessingSystem
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            StringView view = new StringView();
+            view.Run();
+        }
+    }
+}
diff --git a/StringProcessingApp/Services/StringService.cs b/StringProcessingApp/Services/StringService.cs
new file mode 100644
index 0000000..59728cf
--- /dev/null
+++ b/StringProcessingApp/Services/StringService.cs
@@ -0,0 +1,61 @@
+using System;
+
+namespace StringProcessingApp.Services
+{
+    public class StringService
+    {
+        private string currentText = "";
+        private string originalText = "";
+ 
+        public void SetText(string text)
+        {
+            currentText = text;
+            originalText = text;
+        }
+
+        public string GetText()
+        {
+            return currentText;
+        }
+
+        public void ToUpperCase()
+        {
+            currentText = currentText.ToUpper();
+        }
+
+        public void ToLowerCase()
+        {
+            currentText = currentText.ToLower();
+        }
+
+        public int CountCharacters()
+        {
+            return currentText.Length;
+        }
+
+        public bool ContainsWord(string word)
+        {
+            return currentText.Contains(word);
+        }
+
+        public void ReplaceWord(string oldWord, string newWord)
+        {
+            currentText = currentText.Replace(oldWord, newWord);
+        }
+
+        public string ExtractSubstring(int start, int length)
+        {
+            return currentText.Substring(start, length);
+        }
+
+        public void TrimSpaces()
+        {
+            currentText = currentText.Trim();
+        }
+
+        public void ResetText()
+        {
+            currentText = originalText;
+        }
+    }
+}
diff --git a/StringProcessingApp/Views/StringView.cs b/StringProcessingApp/Views/StringView.cs
new file mode 100644
index 0000000..af59f0b
--- /dev/null
+++ b/StringProcessingApp/Views/StringView.cs
@@ -0,0 +1,148 @@
+using System;
+using StringProcessingApp.Services;
+
+namespace StringProcessingApp.Views
+{
+    public class StringView
+    {
+        private StringService service = new StringService();
+
+        public void Run()
+        {
+            bool running = true;
+
+            while (running)
+            {
+                ShowMenu();
+
+                Console.Write("Choose option: ");
+                int choice = Convert.ToInt32(Console.ReadLine());
+
+                switch (choice)
+                {
+                    case 1:
+                        EnterText();
+                        break;
+
+                    case 2:
+                        ViewText();
+                        break;
+
+                    case 3:
+                        service.ToUpperCase();
+                        Console.WriteLine("Converted to UPPERCASE.");
+                        break;
+
+                    case 4:
+                        service.ToLowerCase();
+                        Console.WriteLine("Converted to lowercase.");
+                        break;
+
+                    case 5:
+                        Console.WriteLine("Characters: " +
+                        service.CountCharacters());
+                        break;
+
+                    case 6:
+                        CheckContains();
+                        break;
+
+                    case 7:
+                        ReplaceWord();
+                        break;
+
+                    case 8:
+                        ExtractSubstring();
+                        break;
+
+                    case 9:
+                        service.TrimSpaces();
+                        Console.WriteLine("Spaces trimmed.");
+                        break;
+
+                    case 10:
+                        service.ResetText();
+                        Console.WriteLine("Text reset.");
+                        break;
+
+                    case 11:
+                        running = false;
+                        break;
+
+                    default:
+                        Console.WriteLine("Invalid option.");
+                        break;
+                }
+
+                Console.WriteLine();
+            }
+        }
+
+        private void ShowMenu()
+        {
+            Console.WriteLine("==== STRING PROCESSING SYSTEM ====");
+            Console.WriteLine("1. Enter Text");
+            Console.WriteLine("2. View Current Text");
+            Console.WriteLine("3. Convert to UPPERCASE");
+            Console.WriteLine("4. Convert to lowercase");
+            Console.WriteLine("5. Count Characters");
+            Console.WriteLine("6. Check if Contains Word");
+            Console.WriteLine("7. Replace Word");
+            Console.WriteLine("8. Extract Substring");
+            Console.WriteLine("9. Trim Spaces");
+            Console.WriteLine("10. Reset Text");
+            Console.WriteLine("11. Exit");
+        }
+
+        private void EnterText()
+        {
+            Console.Write("Enter text: ");
+            string text = Console.ReadLine();
+            service.SetText(text);
+        }
+
+        private void ViewText()
+        {
+            Console.WriteLine("Current Text: " +
+            service.GetText());
+        }
+
+        private void CheckContains()
+        {
+            Console.Write("Enter word: ");
+            string word = Console.ReadLine();
+
+            if (service.ContainsWord(word))
+                Console.WriteLine("Word found.");
+            else
+                Console.WriteLine("Word not found.");
+        }
+
+        private void ReplaceWord()
+        {
+            Console.Write("Old word: ");
+            string oldWord = Console.ReadLine();
+
+            Console.Write("New word: ");
+            string newWord = Console.ReadLine();
+
+            service.ReplaceWord(oldWord, newWord);
+
+            Console.WriteLine("Word replaced.");
+        }
+
+        private void ExtractSubstring()
+        {
+            Console.Write("Start index: ");
+            int start = Convert.ToInt32(Console.ReadLine());
+
+            Console.Write("Length: ");
+            int length = Convert.ToInt32(Console.ReadLine());
+
+            string result =
+            service.ExtractSubstring(start, length);
+
+            Console.WriteLine("Substring: " + result);
+        }
+    }
+}