Object-Oriented Programming — from Procedures to Objects

Week 15 · ← Course home · Syllabus · Glossary

Units 07–14 taught you to organize functions (the Functions module) and organize data (the Records module) — in two separate rooms. Object-oriented programming moves the furniture: data and the functions that operate on it travel together, in one package, with rules about who may touch what. That is the whole revolution. Everything else — constructors, const, composition — is craftsmanship applied to it.

One promise and one promise out. In: every idea in this module is a generalization of something you already own — a struct whose functions moved inside, a validated setter from the Records module, the ownership thinking from Pointers. Out: no inheritance, no polymorphism, no virtual functions in this module — they get their own module, Inheritance & Polymorphism, which opens the door once these foundations are yours. (The syllabus says “preview” — the preview is a single honest paragraph at the end of Lesson 3.)

What you already have

You built	In	It becomes
`struct StudentRecord` + free functions	Records module	a class with private data and member functions
Validated `setMark` guard chains	Records module	setters — same rules, new address
The paired `new[]`/`delete[]` cleanup	Pointers module	destructors — the pairing, automated
Menu-driven managers over records	Records, Files, Algorithms mini-projects	the Object-Oriented Mini Project — the same manager, refactored

The module map

Lesson	What it covers
Lesson 1 — Objects, classes, encapsulation	Why OOP; attributes and methods; `public`/`private`; the getter/setter discipline; your first real class
Lesson 2 — Constructors, destructors, lifetime	Default/parameterized/delegating constructors, member initializer lists, destructors, `this`, the object lifetime story
Lesson 3 — Design, const, composition	const member functions; the design method (nouns → data → verbs → interface); composition (has-a) and basic class relationships; `operator<<`; vectors of objects; the inheritance preview
Practice	Exercises — 26 graded with separated solutions · Class design — 10 schema-first design drills · Debugging — 10 seeded hunts · Challenges — 10 with separated solutions
Labs	7 labs — BankAccount, Student, Book, Product, Employee, Course, Library — each a full class design with interface tables, test cases, and solutions
Mini-project	Object-Oriented Mini Project — the Student Record Management System, rebuilt as `Student` + `Roster` classes; file code barely changes

The try-it-first protocol (unchanged)

Solutions are separated from problems everywhere in this module. Design questions especially deserve struggle: a schema sketched in five minutes of honest thought teaches more than five borrowed ones. The design drills exist because class design is a skill, not a syntax fact.

Pacing (Week 15, two sessions)

Session 15.1 — Lessons 1–2 + Exercises Part A + Lab 1 (BankAccount). Encapsulation and constructors are the whole conceptual load of the module; the rest is practice.
Session 15.2 — Lesson 3 + design drills + one lab of your choice + start the mini-project.
Mini-project — finish after Session 15.2; it is the capstone rehearsal for Unit 16.

Self-check — you are ready for Unit 16 when…

You can say why mark lives under private in your own words, without the word “best practice”
You can write a class’s constructor with a member initializer list and say why it beats assignment in the body
You can mark every member function const that can be — and justify the ones that can’t
You can explain, with a diagram, why Roster has-a Student but is not a Student
You have refactored a procedural program into classes and can name what got better

Where this leads

Unit 16’s capstone (Contact Management System) is this module’s mini-project with a new skin — same classes, same file contract, more features. The vocabulary you built here (private, constructors, const, composition) is exactly the vocabulary every data-structures course assumes. Inheritance waits outside the door; you don’t need it yet.

— Engr. Dr. Muhammad Nadeem Majeed, Professor, Department of Data Science (PUCIT), University of the Punjab, Lahore · About the instructor