Kotlin Recipes vs IQ

Tap Run and the real output appears right under the code, so you know what it does before it goes into your project. No Kotlin to install, no IDE, no setup, no account. 390+ short examples, one task each. Over 95% run on Kotlin 2.4. You know what you need, but not the exact syntax: • How do I fall back to a default value when a variable is null? • How do I return two values from a function? • How do I merge two maps? Each has a working example here. • 24 sections, including strings and dates, collections, nullable types, classes and interfaces, enums, generics, extension functions, lambdas, exception handling, regular expressions, multithreading, files, JSON and XML, algorithms, and design patterns. • What changed from Kotlin 1.4 to 2.0, with before-and-after code: value classes, sealed interfaces, data objects and the improved smart casts in Kotlin 2.0. • Reference, 320+ entries: keywords and standard library functions for strings, collections, files, and coroutines. Tap a word in the code to look it up. • 200+ SQL queries: JOIN, GROUP BY, subqueries, window functions; more than half run on a practice database. • Search looks inside the code: type joinToString to find every example that uses it. • Edit an example and run your version, or write your own. • Works on iPhone, iPad, and Mac. • Everything except running code works offline. Free version: 210+ Kotlin examples and 120+ SQL queries, the full reference, and 12 runs and 12 edits a day (Kotlin and SQL runs share one limit). Full version: all examples and queries, unlimited edits and examples of your own, and up to 30 Kotlin and 80 SQL runs a day. One-time purchase, no subscription. Built by a developer for developers. The project behind it has been in active development since 2015.

Multithreading, memory, architecture. New AI mode based on Foundation Models, hardcore challenges, and global rankings. Are you preparing for a Middle/Senior interview or just want to keep your brain in shape? I've collected and packaged everything that's asked in technical interviews into one app and added a powerful task generation engine. What's inside? Fundamentals: hardcore questions on topics to think about. Multithreading: GCD, Operations, Actors, data races. Memory management: ARC subtleties, retain cycles, and much more. Algorithms: From Big O to trees and graphs. Architectures: Breaking down MVC, MVVM, VIPER, TCA. Compiler and runtime: How Swift works under the hood. Infinite task generator The main feature of the update is Dynamic Mode. The app generates unique cases and questions in real time. This allows you to not only memorize the correct answer, but also to truly understand how a particular technology works by encountering new formulations each time. Training modes Time sprint: Live coding stress simulation. Learn to think fast. One mistake: “First mistake” mode. For those who are confident they know the documentation by heart. Progress and Rating Detailed statistics will show your weak areas (for example, if you are good at UI but struggle with algorithms). And the global leaderboard will help you compare your grade with other developers in the community. Adjust the difficulty to suit yourself, choose topics, and download skills.