Week 8 : Mastering OOP Inheritance



This content originally appeared on DEV Community and was authored by Adhyan Jain

As part of my #100DaysOfCode challenge, I dedicated Days 50-56 to mastering inheritance in object-oriented programming. Here’s a summary of my journey through different inheritance patterns and what I learned along the way.

Day 50: Basic Inheritance

I started with the fundamental parent-child class relationship:

Electronics Store: Created a Device base class with Television & Refrigerator subclasses
Sales Assistant: Implemented inheritance for displaying product details & calculating metrics
Product Cost Calculator: Used hierarchical inheritance for electronic & mechanical device pricing

These projects demonstrated how inheritance promotes code reuse and specialization while maintaining a clear hierarchy.

Day 51: Multiple Inheritance

Multiple inheritance allows a class to inherit from more than one base class:

Loan Calculator: Designed Principal & InterestRate classes with Loan inheriting from both
Ticket Booking System: Built a system handling both concert & movie tickets
Academic Performance Tracker: Created a Student class inheriting from GPA & CreditHours classes

The challenge here was understanding potential ambiguity issues when classes inherit from multiple sources.

Day 52: Multi-level Inheritance

Next, I explored multi-level inheritance, which creates chains of inheritance:

Financial Calculator: Built Investment → FixedDeposit → SimpleInterest inheritance chain
Order Cost Calculator: Implemented Order → FinalOrder → DiscountedOrder structure
Social Media System: Designed User → Blogger → Influencer class hierarchy

This pattern helped me understand how behavior accumulates through inheritance levels.

Day 53: Protected Members

Day 53 focused on access modifiers, particularly protected members:

Cylinder Volume Calculator: Created Circle base class with protected radius
Electrical Power Calculator: Implemented base class P with voltage & current attributes
Vehicle Rental System: Built Vehicle base class with Car & Motorcycle subclasses

These projects demonstrated how protected members strike a balance between encapsulation and inheritance.

Day 54: Hybrid Inheritance

Hybrid inheritance combines multiple inheritance types:

Dual Role Manager: Created a TeachingAssistant class inheriting from both Student & Employee
Multi-operation Calculator: Built child classes with inherited operations
Online Store System: Implemented hybrid inheritance for electronics & clothing products

This complex pattern taught me how to model sophisticated real-world relationships.

Day 55: Constructor Overloading

While not strictly an inheritance concept, constructor overloading pairs naturally with inheritance:

Goods Cost Calculator: Implemented default & parameterized constructors
Simple Interest Calculator: Created multiple constructors for different initialization scenarios
Forest Rainfall Calculator: Used constructor overloading for square & rectangular areas

This reinforced how constructors work across inheritance hierarchies.

Day 56: Function Overloading

I concluded with function overloading:

Minimum Value Finder: Created overloaded functions for different data types
Unit Converter: Implemented overloaded conversion functions
Shopping Cart: Designed overloaded price calculation functions for various scenarios

This exercise demonstrated how polymorphism complements inheritance to create flexible interfaces.

Key Takeaways

After a week of intensive practice, I gained several valuable insights:

  1. Inheritance is powerful but requires planning – Poor hierarchies lead to rigid code
  2. Access modifiers matter – Protected members are crucial for proper inheritance
  3. Real-world modeling – The best inheritance hierarchies mirror natural relationships

Has anyone else tackled similar inheritance challenges? Which inheritance pattern do you find most useful in production code?


This content originally appeared on DEV Community and was authored by Adhyan Jain