Adding problem 6 from Final Spring 2026.

Author: aubertc

source/code/projects/UserFoundSecretWord/UserFoundSecretWord/Program.cs

@@ -0,0 +1,22 @@
+using System;
+
+class Program
+{
+  static void Main()
+  { 
+    string stringtest;
+    bool booltest = Demo.UserFoundSecretWord(out stringtest);
+    Console.WriteLine("The method returned " + booltest + " after you entered \"" + stringtest + "\".");
+  }
+}
+
+public static class Demo{
+  // Beginning of solution.
+  public static bool UserFoundSecretWord(out string uInput){
+    Console.WriteLine("Enter a string");
+    uInput = Console.ReadLine();
+    if(uInput == null) throw new ArgumentNullException();
+    return uInput.Contains("scytale");
+  }
+  // End of solution.
+}

source/solutions/oop/references.md

@@ -120,6 +120,25 @@ tags:
 
 ## Problems
 
+#. Knowing that our secret word is "[scytale](https://en.wikipedia.org/wiki/Scytale)", write a `UserFoundSecretWord` method that
+
+    - asks the user for a `string`,
+    - throws an `ArgumentNullException` exception if the string entered is `null`,
+    - returns `true` if the string entered contains `"scytale"`, `false` otherwise,
+    - stores the string entered in the `uInput` reference variable.
+    
+    with the following header, where you need to fill in `_________`:
+
+    ```
+    public static bool UserFoundSecretWord(_________ string uInput){
+    ```
+    
+    <details><summary>Solution</summary>
+    ```{download="./code/projects/UserFoundSecretWord.zip"}
+    !include`snippetStart="// Beginning of solution.",snippetEnd="// End of solution."` code/projects/UserFoundSecretWord/UserFoundSecretWord/Program.cs
+    ```
+    </details>
+    
 #. Write the `AddLog` method (header included) such that the following:
 
     ```{download="./code/projects/ReferenceMethods.zip"}