Topic 7. Classes and objects: fields, properties, constructors

Goal: learn the basic concepts of object-oriented programming: classes, objects, state, and behavior; learn to declare classes with fields, properties, constructors, and methods, create objects, and work with arrays of objects; master object state validation in properties and constructors.

Lecture contents

1. Classes, objects, and fields — The object-oriented approach · Declaring a class · Creating objects and reference semantics · Fields, methods, and this
2. Properties and constructors — Properties · Constructors
3. Initializers, ToString, and conventions — Object initializers · The ToString method and inspecting objects · Object lifetime · Naming conventions
4. Examples and common mistakes — Example programs · Common mistakes

Practice and review

• Practice — 3 worked examples with complete code and output
• Tasks — 30 variants, each with tasks at three difficulty levels
• Summary — conclusions, self-check questions, and useful links