Geometry

Complete version (all in one file) - All 57 sections combined in a single document for easy reading or printing.

Teaching note: Three ways to give a Circle a centre - constructor parameters versus attributes, and UML association versus composition. See also Circle and Point constructors.

Table of Contents

• 1 - Introduction to OOP
• 1.1 Summary
• 1.2 Creating a class
• 1.3 Using a class
• 1.4 Constructors
• 1.5 Static versus non-static
• 1.6 Class diagram
• 2 - Encapsulation and constructor chaining
• 2.1 Summary
• 2.2 Encapsulation
• 2.3 Constants
• 2.4 Constructor chaining
• 2.5 Arrays of objects
• 2.6 Class diagram
• 3 - Classes as attribute (Point, Circle, Rectangle)
• 3.1 Summary
• 3.2 Classes as attribute
• 3.3 Class diagram
• 3.4 Relationship between Circle and Point
• 3.5 The Rectangle class
• 3.6 Class diagram
• 3.7 Code for Point class
• 3.8 Code for Rectangle class
• 4 - Inheritance and ToString
• 4.1 Summary
• 4.2 Shape base class
• 4.3 Circle as derived class
• 4.4 Rectangle as derived class
• 4.5 Class diagram
• 4.6 ToString method
• 4.7 Code for Shape class
• 5 - Polymorphism and abstract classes
• 5.1 Summary
• 5.2 Polymorphism
• 5.3 Abstract classes
• 5.4 Class diagram
• 5.5 Nullable and value types
• 6 - Lists and type checking (is/as)
• 6.1 Summary
• 6.2 List
• 6.3 For loop through List
• 6.4 Surface class
• 6.5 Type checking and casting
• 6.6 Class diagram
• 7 - Interfaces (IComparable)
• 7.1 Summary
• 7.2 IComparable interface
• 7.3 Class diagram
• 8 - Exceptions
• 8.1 Summary
• 8.2 Exceptions
• 9 - File input and output
• 9.1 Summary
• 9.2 Reading from a file
• 9.3 Writing to a file
• 10 - Database access (ADO.NET with MySQL)
• 10.1 Summary
• 10.2 Setting up database and writing points
• 10.3 Reading points
• 10.4 DbAccess class
• 10.5 PointDao class
• 10.6 CircleDao class
• 10.7 Auto-increment values
• 11 - Database continued (AbstractDao)
• 11.1 Summary
• 11.2 AbstractDao class
• 11.3 Adapt PointDao
• 11.4 Refactor CircleDao

Structure

Each chapter is in its own folder with separate markdown files per section. Use the Table of Contents above to jump to any section.

Image List

Images Overview - All 18 images on one page with descriptions.

Description and image link	Used in
Circle with public radius, centre coordinates, colour, perimeter and area operations	1.2 Creating a class
Autocompletion	1.3 Using a class
Circle with three constructors, perimeter and area methods, static Definition and static member	1.6 Class diagram
Encapsulated Circle with private fields, properties, constant LimitValueForBigShape, DescribeSize and static Definition	2.6 Class diagram
Point with X and Y, private backing fields, properties and chained constructors	3.2 Classes as attribute
Circle with Point centre reference, radius, colour, geometry operations and static Definition	3.3 Class diagram
Circle and Point with many-to-one association: each Circle has one Centre Point	3.4 Relationship between Circle and Point
Point, Circle and Rectangle with centre or corner links to Point and full operation sets	3.6 Class diagram
Shape base class with protected colour, default colour constant, virtual area and perimeter, DescribeSize and static Definition	4.2 Shape base class
Shape superclass with Circle and Rectangle subclasses, each composed of Point	4.5 Class diagram
Abstract Shape with abstract CalculateArea and CalculatePerimeter, colour and DescribeSize	5.4 Class diagram
Surface layout with rectangles	6.4 Surface class
Surface layout with rectangles and circles	6.4 Surface class
Abstract Shape, Circle, Rectangle, Point and Surface holding a list of shapes on a sized canvas	6.6 Class diagram
Shape family and Surface plus IComparable of Shape for ordering shapes	7.3 Class diagram
DbAccess with connection string, MySqlConnection and OpenConnection, GetConnection, CloseConnection	10.4 DbAccess class
AbstractDao base class storing DbAccess for shared database access in concrete DAOs	11.2 AbstractDao class
DbAccess used by AbstractDao; PointDao and CircleDao inherit and add SavePoint, SaveCircle and queries	11.4 Refactor CircleDao

Supporting files

• Rectangle.csv, CreateInsertScriptShapes.sql

Conventions

• Language: English (translated from Dutch)
• Code: C# with .NET 8
• Conventions: C# Coding Standards
• Data folder: Data/Rectangle.csv for chapter 9; Data/CreateInsertScriptShapes.sql for chapters 10-11

Database (chapters 10-11)

1. Run Data/CreateInsertScriptShapes.sql in MySQL Workbench
2. Add NuGet package: MySql.Data
3. Adjust connection string if your MySQL setup differs

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