- Z80 Emulator
- Gameboy emulator
- Mini programming language
- Scientific calculator
- Json parser
- Videogame
- Video / Audio encoder
- Trading engine
- Auction house
- Regex engine
- Data structures
- Examples: C Template library, GLib, Boost Heaps, Abseil data structures
- Hash Table
- Trie
- Rope
- B-Tree
- LRU Cache
- Matrix library
- Modular integers library
- Galois field library
- Gist clone
- Static website generator
- Pastebin
- Fuzzy text search / Text autocomplete
- Parallel data structures
- HTTP server
- IRC bot
- Go game engine
- Encryption algorithms
- Hashing algorithms (explore collisions)
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