🎯 Object-Oriented Programming — Complete Study Roadmap
Goal: Master OOP from zero to interview-ready Language: C++ (with Java equivalents noted) Total Estimated Time: 2-3 weeks of focused study
Learning Path
Week 1: Foundations
┌──────────────────┐ ┌──────────────────────────┐ ┌─────────────────┐
│ 01 - Classes, │────►│ 02 - Encapsulation & │────►│ 03 - Inheritance│
│ Objects, Ctors │ │ Abstraction │ │ │
│ (2 days) │ │ (2 days) │ │ (2 days) │
└──────────────────┘ └──────────────────────────┘ └────────┬────────┘
│
Week 2: Core Principles ▼
┌──────────────────┐ ┌──────────────────────────┐ ┌─────────────────┐
│ 05 - SOLID │◄────│ 04 - Polymorphism │◄────│ │
│ Principles │ │ │ │ │
│ (2 days) │ │ (2 days) │ └─────────────────┘
└────────┬─────────┘ └──────────────────────────┘
│
Week 3: Mastery
▼
┌──────────────────┐ ┌──────────────────────────┐ ┌─────────────────┐
│ 06 - Design │────►│ 07 - Advanced OOP │────►│ 08 - Real-World │
│ Patterns │ │ │ │ & Interviews │
│ (3 days) │ │ (2 days) │ │ (2 days) │
└──────────────────┘ └──────────────────────────┘ └─────────────────┘Module Overview
| # | Module | Topics | Est. Time |
|---|---|---|---|
| 01 | Classes, Objects & Constructors | Class vs Object, constructors (default, parameterized, copy, move), destructors, this pointer, static members, const correctness | 2 days |
| 02 | Encapsulation & Abstraction | Access modifiers, getters/setters, data hiding, abstract classes, interfaces, friend, information hiding | 2 days |
| 03 | Inheritance | Single, multiple, multilevel, hierarchical, hybrid, diamond problem, virtual inheritance, override, final | 2 days |
| 04 | Polymorphism | Compile-time (overloading, templates), runtime (virtual functions, vtable, dynamic dispatch), operator overloading, RTTI | 2 days |
| 05 | SOLID Principles | SRP, OCP, LSP, ISP, DIP — each with real-world C++ examples and violations | 2 days |
| 06 | Design Patterns | Creational (Singleton, Factory, Builder), Structural (Adapter, Decorator, Proxy), Behavioral (Observer, Strategy, Command) | 3 days |
| 07 | Advanced OOP | Composition vs Inheritance, Mixins (CRTP), Abstract vs Interface, DI, RAII, Rule of 3/5/0, smart pointers | 2 days |
| 08 | Real-World & Interview Prep | Project walkthroughs, UML basics, 100+ interview questions, coding challenges | 2 days |
The Four Pillars of OOP
┌─────────────────────────────────────────────────────────────┐
│ OBJECT-ORIENTED PROGRAMMING │
├───────────────┬───────────────┬───────────────┬─────────────┤
│ ENCAPSULATION │ ABSTRACTION │ INHERITANCE │ POLYMORPHISM│
│ │ │ │ │
│ Bundle data + │ Hide complex │ Reuse code │ One inter- │
│ methods into │ implementation│ from parent │ face, many │
│ a single unit │ Show only what│ classes │ forms │
│ │ is needed │ │ │
│ Access │ Abstract │ Base/Derived │ Overloading │
│ Modifiers │ Classes │ Classes │ Overriding │
│ Getters/ │ Interfaces │ Virtual │ Virtual │
│ Setters │ Pure Virtual │ Inheritance │ Functions │
└───────────────┴───────────────┴───────────────┴─────────────┘How to Use This Curriculum
- Follow the order — each module builds on the previous
- Type every code example — don't just read, compile and run
- Solve practice problems before reading solutions
- Answer interview questions out loud (practice explaining)
- Build the real-world project in Module 08
Interview Readiness Checklist
Fundamentals:
[ ] Can explain class vs object with an example
[ ] Understand all constructor types (default, param, copy, move)
[ ] Know the Rule of 3/5/0
[ ] Can explain the `this` pointer and static members
Pillars:
[ ] Can explain encapsulation with getters/setters
[ ] Understand abstraction vs encapsulation (they're different!)
[ ] Can explain all inheritance types and the diamond problem
[ ] Understand compile-time vs runtime polymorphism
[ ] Can explain how vtable and vptr work
Principles:
[ ] Can explain all 5 SOLID principles with examples
[ ] Can identify violations and suggest fixes
[ ] Understand Liskov Substitution deeply (the tricky one)
Patterns:
[ ] Know at least Singleton, Factory, Observer, Strategy
[ ] Can implement any pattern from memory
[ ] Know when to use which pattern
Advanced:
[ ] Prefer composition over inheritance (and know why)
[ ] Understand RAII and smart pointers
[ ] Can design a class hierarchy for a real-world problem
[ ] Can draw basic UML class diagrams