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    C# Language: all courses in this track

    Guided course · C# Language

    C# From First Program to Confident Developer

    Learn C# from your first console program through intermediate and advanced engineering with .NET 10. Follow 36 sequenced lessons in 12 modules: core syntax and design, object contracts and generic APIs, data pipelines, reliable asynchronous services, concurrency and backpressure, memory and runtime behavior, reflection, measurement and a bounded-import capstone, then a closing Final Quiz in a 13th module. Each of the 36 lessons includes worked examples, analogies with their limits, exercises and solutions, quick references, interview questions with reasoned answers, and its own 10-question practice test. The first three lessons, their practice tests and the closing Final Quiz (15 questions, 20 minutes) are free; the remaining 33 lessons are included in existing TechInterviewNotes Full Access. Start at the beginning or use each module's prerequisites to continue from the appropriate level.

    Foundation13 modules · 37 lessons · 5 h 58 min · 36 practice tests · 4 free
    Start the courseSave

    Module 1 · First Steps

    Free preview3 lessons · 24 min
    1. 01Your First C# Program: Build, Run and Understand ItFree, 1 practice test8 min
    2. 02Values, Expressions and Reliable InputFree, 1 practice test8 min
    3. 03Decisions, Loops and Tracing Program StateFree, 1 practice test8 min

    Module 2 · Functions and Everyday Data

    3 lessons · 24 min
    1. 04Methods, Parameters and Small Responsibilities (included with Full Access), 1 practice test8 min
    2. 05Arrays, Lists and Dictionaries: Choose the Right Collection (included with Full Access), 1 practice test8 min
    3. 06Strings, Nullability and Validation Boundaries (included with Full Access), 1 practice test8 min

    Module 3 · Objects and Design

    3 lessons · 24 min
    1. 07Classes, Properties and Valid State (included with Full Access), 1 practice test8 min
    2. 08Values, References, Records and Equality (included with Full Access), 1 practice test8 min
    3. 09Interfaces, Composition and Replaceable Boundaries (included with Full Access), 1 practice test8 min

    Module 4 · Reliable C# Programs

    3 lessons · 24 min
    1. 10Exceptions, Disposal and File Boundaries (included with Full Access), 1 practice test8 min
    2. 11Generics, Delegates and Lambdas (included with Full Access), 1 practice test8 min
    3. 12LINQ: Queries, Deferred Work and Snapshots (included with Full Access), 1 practice test8 min

    Module 5 · Asynchronous Work and Verification

    3 lessons · 24 min
    1. 13Async, Await and Cooperative Cancellation (included with Full Access), 1 practice test8 min
    2. 14Testing Behavior and Debugging Failures (included with Full Access), 1 practice test8 min
    3. 15Pattern Matching and Explicit State Decisions (included with Full Access), 1 practice test8 min

    Module 6 · Build and Defend a Complete Application

    3 lessons · 30 min
    1. 16JSON Persistence and Safe Loading (included with Full Access), 1 practice test9 min
    2. 17Capstone: Build a C# Study Planner (included with Full Access), 1 practice test11 min
    3. 18Capstone Review: Edge Cases, Refactoring and Interview Defense (included with Full Access), 1 practice test10 min

    Module 7 · Intermediate: Object Contracts and Generic APIs

    3 lessons · 32 min
    1. 19Inheritance and Polymorphism: Contracts You Can Substitute (included with Full Access), 1 practice test10 min
    2. 20Generic Constraints and Variance: Designing Typed APIs (included with Full Access), 1 practice test11 min
    3. 21Events and Delegate Lifetimes: Publish Changes Safely (included with Full Access), 1 practice test11 min

    Module 8 · Intermediate: Query and Data Pipelines

    3 lessons · 33 min
    1. 22Iterators and Streaming: Yield, Enumeration and Ownership (included with Full Access), 1 practice test11 min
    2. 23LINQ Grouping and Joins: Model Data Relationships (included with Full Access), 1 practice test11 min
    3. 24Equality and Ordering: Reliable Keys and Deterministic Results (included with Full Access), 1 practice test11 min

    Module 9 · Intermediate: Robust Asynchronous Services

    3 lessons · 30 min
    1. 25Concurrent Tasks: Results, Failures and Cancellation (included with Full Access), 1 practice test10 min
    2. 26HTTP Boundaries: Reuse Clients, Validate Responses, Cancel Work (included with Full Access), 1 practice test10 min
    3. 27Time and Reliability: TimeProvider, Timeouts and Repeatable Tests (included with Full Access), 1 practice test10 min

    Module 10 · Advanced: Concurrency and Backpressure

    3 lessons · 30 min
    1. 28Shared State: Locks, Interlocked and Safe Invariants (included with Full Access), 1 practice test10 min
    2. 29Channels: Bounded Pipelines and Completion (included with Full Access), 1 practice test10 min
    3. 30Async Streams: IAsyncEnumerable and Cancellation (included with Full Access), 1 practice test10 min

    Module 11 · Advanced: Memory and Runtime Behavior

    3 lessons · 30 min
    1. 31Allocation and GC: Measure Lifetimes Before Optimizing (included with Full Access), 1 practice test10 min
    2. 32Span and Memory: Slices, Ownership and Async Boundaries (included with Full Access), 1 practice test10 min
    3. 33Structs, Boxing and Ref Semantics: Copy Costs and Correctness (included with Full Access), 1 practice test10 min

    Module 12 · Advanced: Architecture and Delivery

    3 lessons · 33 min
    1. 34Reflection, Attributes and Trimming-Aware Design (included with Full Access), 1 practice test10 min
    2. 35Benchmarking and Diagnostics: Measure Claims Responsibly (included with Full Access), 1 practice test11 min
    3. 36Advanced Capstone: Bounded Import Pipeline and Failure Recovery (included with Full Access), 1 practice test12 min

    Module 13 · Practice and Assessment

    1 lesson · 20 min
    1. 37Final Quiz: 15 Questions on C# From First Program to Confident DeveloperFree20 min