$ show ashishps1/awesome-low-level-design
This repository is an educational resource focused on teaching low-level design (LLD) and object-oriented design (OOD) principles through runnable code examples. It contains implementations of the Gang of Four design patterns (creational, structural, behavioral) across multiple programming languages including C++, Java, C#, Python, Go, and JavaScript/TypeScript. Additionally, it provides problem statements and solutions for common LLD interview questions such as parking lot systems, ATM implementations, vending machines, and social networking platforms. The repository serves as both a reference guide and a practical learning tool. Each design pattern is demonstrated with minimal, focused examples that isolate the pattern's core mechanics. The problem/solution sections show how these patterns can be applied in real-world scenarios, complete with class diagrams and explanations. While the code is functional and demonstrative, it prioritizes clarity of concept over production robustness, making it ideal for learning but requiring adaptation for actual deployment. Although primarily educational, the repository contains executable code that could be considered a collection of mini-applications. Each pattern implementation and problem solution can be run independently to observe the behavior. The multi-language approach allows developers to compare how the same pattern is expressed in different ecosystems, highlighting both universal principles and language-specific idioms.
The LLM identified 3 files worth highlighting for reuse:
Implements the Strategy pattern for calculating shipping costs based on distance. Demonstrates clean separation of algorithm (shipping cost calculation) from context (shipping service). The implementation is self-contained with clear interface (shipping_strategy.h) and concrete strategies, making it easily extractable for use in any logistics or e-commerce system.
Provides a clear implementation of the Observer pattern for fitness data monitoring. Defines subject (fitness_data) and observer (fitness_data_observer) interfaces with concrete implementations showing how multiple observers can subscribe to data updates. The example is loosely coupled and demonstrates the pattern's core mechanics without domain-specific complexity.
Shows a thread-safe lazy initialization Singleton pattern using double-checked locking. The implementation is isolated, requiring no external dependencies, and demonstrates proper synchronization techniques. This component could be directly reused in any application needing a globally accessible, lazily initialized single instance.