LRU Cache (C++)

A C++ implementation of an LRU (Least Recently Used) cache that supports constant-time get and put operations.
The project includes an interactive command-line demo and basic tests to verify correctness.

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Features

• Fixed-capacity cache with automatic eviction
• O(1) average-time get and put operations
• Least recently used item is evicted when capacity is exceeded
• Interactive CLI to experiment with cache behavior
• Simple assertion-based tests

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Tech Stack

• C++
• STL (std::unordered_map, std::list)
• CMake

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How It Works

• A hash map provides fast lookup from key to cache entry
• A doubly linked list tracks usage order
• Most recently used items are kept at the front
• Least recently used items are removed when the cache is full

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How to Run

Requirements

• C++ compiler that supports C++17
• CMake
• An IDE such as CLion, or a terminal environment

Steps

1. Clone the repository to your local machine.
2. Open the project folder in your IDE (for example, CLion).
3. Build the project using CMake.
4. Run the lru_cache target to start the interactive demo.
5. Follow the on-screen instructions to interact with the cache.

Demo

1. Build and run the lru_cache target.
2. Enter a cache capacity when prompted.
3. Use the following commands:
   • put <key> <value> — insert or update an entry
   • get <key> — retrieve a value
   • print — display cache contents (MRU → LRU)
   • quit — exit the program