Added solution to Quiz #6.

Author: aubertc

source/solutions/oop/inheritance.md

@@ -16,6 +16,17 @@ tags:
     - [ ] `over`
     - [ ] `inherits`
 
+#. Inheritance is …
+
+    - [x] … a way of implementing a class by re-using another class' code.
+    - [ ] … impossible to represent in a UML diagram.
+    - [ ] … achieved using the `;` (semicolon) symbol.
+    - [ ] … a way of connecting a *basic* class with a *derived* class.
+
+    <details><summary>Comment</summary>
+        The class inherited from is called the *base*, superclass or parent class, but not *basic*.
+    </details>
+    
 #. Suppose your are given an `ElectricDevice` class and a `WallDecor` class. You would like to write a `Clock` class that represents at the same time an electric device and a wall decor. This is possible only if the `ElectricDevice` and `WallDecor` classes are…
 
     - [ ] Sealed
@@ -38,6 +49,26 @@ tags:
 
 ## Problems
 
+#. Assume given the following class implementation:
+
+    ```
+    !include code/projects/Computer/Computer/Computer.cs
+    ```
+    
+    Write a `Laptop` class that
+    
+    #. Inherits from `Computer`,
+    #. Has one single (automatic) property, called `ScreenSize`, of type `int`,
+    #. Has a constructor that takes 2 parameters of appropriate datatypes, and use them to set `brand` and `ScreenSize`,
+    #. Has a `ToString` method that returns a `string` containing the brand and screen size.
+    
+
+        <details><summary>Solution</summary>
+        ```{download="code/projects/Computer.zip"}
+        !include code/projects/Computer/Computer/Laptop.cs
+        ```
+        </details>
+
 #. Consider the diagram representing the "Room", "ClassRoom", "Office" classes and their relations.
 
     !include diag/cla/RoomClassroomOffice.md