Added second finale exercises.

Author: aubertc

source/code/projects/Article/Article/Article.cs

@@ -0,0 +1,32 @@
+using System;
+
+abstract class Article
+{
+  public string Id { get; set; }
+  private decimal price;
+
+  public void SetPrice(decimal priceP)
+  {
+    if (priceP < 0)
+    {
+      throw new ArgumentOutOfRangeException();
+    }
+    else
+    {
+      price = priceP;
+    }
+  }
+
+  public decimal GetPrice()
+  {
+    return price;
+  }
+
+  public Article(string idP, decimal priceP)
+  {
+    Id = idP;
+    SetPrice(priceP);
+  }
+
+  public abstract decimal ShippingCosts();
+}

source/code/projects/Article/Article/Book.cs

@@ -0,0 +1,20 @@
+class Book : Article
+{
+  public string Title { get; set; }
+
+  public Book(string idP, decimal priceP, string titleP)
+    : base(idP, priceP)
+  {
+    Title = titleP;
+  }
+
+  public override decimal ShippingCosts()
+  {
+    decimal tenp = .1M * GetPrice();
+    if (tenp > 5M)
+    {
+      tenp = 5M;
+    }
+    return tenp;
+  }
+}

source/code/projects/Article/Article/Program.cs

@@ -0,0 +1,15 @@
+using System;
+
+class Program
+{
+  public static void Main()
+  {
+    Book test = new Book(
+      "AAA001",
+      12.5M,
+      "What it's like to be a bird."
+    );
+    Console.WriteLine($"{test.ShippingCosts():C}");
+    Console.WriteLine(test.Id);
+  }
+}

source/solutions/oop/inheritance.md

@@ -19,7 +19,7 @@ tags:
 
 ## Problem
 
-#. Consider the following diagram:
+#. Consider the diagram representing the "Room", "ClassRoom", "Office" classes and their relations.
 
   !include uml/cla/RoomClassroomOffice.md
 
@@ -56,21 +56,41 @@ tags:
       ```
       </details>
 
-#. Consider the following diagram:
+#. Consider the diagram representing the "Article", "Book" classes and their relations.
 
       !include uml/cla/Article.md
 
     #. Write a (partial) implementation of the `Article` abstract class:
 
-        #. Write an implementation for the `price` attribute: you can either use a getter and a setter (as pictured in the UML diagram), or a property. However, in both cases, setting the price to a negative value should result in an `ArgumentOutOfRangeException` (that you can shorten to `AOORE`) exception being thrown.
+        #. Write an implementation for the `price` attribute: you can either use a getter and a setter (as pictured in the UML diagram), or a property. However, in both cases, setting the price to a negative value should result in an `ArgumentOutOfRangeException` exception being thrown.
         #. Write an *abstract* `ShippingCosts()` method.
 
+        <details><summary>Solution</summary>
+        ```
+        !include code/projects/Article/Article/Article.cs
+        ```
+        </details>
+
+        
     #. Now, assume given a complete implementation of the `Article` abstract class. Write a **complete** implementation of the `Book` class (header included), containing:
         #. An implementation of the `Title` property using auto-properties.
         #. A `Book` constructor that passes the `idP` and `priceP` arguments to the `Article` constructor. The `titleP` argument should be assigned to the `Title` property.
-        #. A `ShippingCosts()` method that returns either $5.0$, or 10% of the Book's price, whichever is smallest.
+        #. A `ShippingCosts()` method that returns either 5.0, or 10% of the Book's price, whichever is smallest.
+    
+        <details><summary>Solution</summary>
+        ```
+        !include code/projects/Article/Article/Book.cs
+        ```
+        </details>
 
     #. Write statements that, if placed in a `Main` method, would
         #. Create a `Book` with `Id` "AAA001", `price` $12.5, titled "What it's like to be a bird".
         #. Display (nicely) its shipping costs.
         #. Display its `Id` (as retrieved from the object).
+
+        <details><summary>Solution</summary>
+        ```{download="code/projects/Article.zip"}
+        !include code/projects/Article/Article/Program.cs
+        ```
+        </details>
+