Study Guide Hub

Study Guide Hub is your pocket-sized companion for technical interview prep and everyday programming reference — built for developers who want to truly understand what they're writing. Whether you're preparing for a coding interview, brushing up after a break, or learning the fundamentals for the first time, Study Guide Hub turns dense documentation into focused, digestible guides you can actually learn from — anywhere, even offline. 10 STRUCTURED GUIDES • C# / .NET — type system, async/await, LINQ, generics, memory management, and modern C# features • Python — data types, closures, comprehensions, OOP, asyncio, and the CPython runtime model • JavaScript — types and coercion, closures, the event loop, prototypes, and modern ES features • TypeScript — types, generics, narrowing, utility and mapped types, and strictness • Java — core language, collections, generics, concurrency, and the JVM • Go — goroutines, channels, interfaces, generics, and the runtime • Rust — ownership, borrowing, lifetimes, traits, and fearless concurrency • C++ — RAII, smart pointers, move semantics, templates, and the STL • Scala — functional and object-oriented features, collections, and pattern matching • Angular — components, services, RxJS, signals, routing, and app structure • Every section pairs clear explanations with real, syntax-highlighted code examples LEARN BY DOING • A worked code example on every section • "In Practice" — see how each concept is applied in real-world scenarios across finance, healthcare, logistics, and more • Knowledge Check — a quick self-test at the end of every section FILTER BY DIFFICULTY • Focus any guide by Beginner, Intermediate, or Advanced • Skip what you've mastered and drill into what you haven't QUIZ MODE • Multiple-choice or flashcard style — your pick • Spaced-repetition review (SM-2) brings each question back right before you'd forget it • Grade your recall — Again, Hard, Good, or Easy — to tune the schedule • Fully offline; your review schedule is saved on-device PROGRESS & FAVORITES • Mark sections complete to track your study progress • Favorite any section for instant access • Saved locally — no account required FREE & STUDY GUIDE HUB PRO • Free: the complete C# / .NET guide, daily quiz practice, and favorites • Unlock Pro once to open all 10 guides — Python, JavaScript, TypeScript, Java, Go, Rust, C++, Scala, and Angular — plus unlimited quiz and unlimited favorites • A one-time purchase. No subscription, no account. 100% OFFLINE • All content lives on your device — study on a plane, on the subway, or anywhere without a signal DARK & LIGHT MODE • Follows your system appearance automatically Available in English and Spanish. Study Guide Hub is built by Triangulum — a small team of developers who wanted better study tools for themselves.