Learn C# from first program to production API

Start with no assumed programming knowledge: learn what code does, how C# and .NET fit together, and run your first program.

Learn why programs name values, how types prevent invalid operations, and how to choose types for text, counts, measurements, money, and state.

Turn numeric values into reliable calculations and learn where integer division, rounding, precedence, and overflow can surprise you.

Build, inspect, compare, and normalize text while understanding why strings behave differently from mutable containers.

Accept text from a user, convert it safely, and keep invalid input from becoming invalid program state.

Turn rules into true-or-false expressions, choose among paths with if and switch, and avoid overlapping or unreadable conditions.

Repeat work without copying statements, trace loop state safely, and choose for, while, do-while, or foreach from the problem.

Separate compiler errors, runtime failures, and wrong results, then use evidence to locate causes instead of guessing at fixes.

Name a reusable operation, pass only the information it needs, return a useful result, and keep Main from becoming the whole program.

Understand where names exist, why local changes sometimes stay local, and how reference-type objects can be shared between callers and methods.

Store related values in order, select a fixed or growable collection, and traverse safely without confusing length, count, and indexes.

Look up values by meaningful keys, track unique membership, and choose between ordered sequences, mappings, and sets.

Represent missing data honestly, distinguish missing from empty or zero, and use nullable analysis and explicit defaults without hiding mistakes.

Move from loose variables to domain objects that keep related state and behavior together without treating every noun as a class.

Create objects in valid states, control how state changes, and design a small public surface that protects domain rules.

Choose a type shape based on identity, value equality, mutability, and valid states instead of defaulting every model to a class.

Program to a small capability, combine objects to build behavior, and reserve inheritance for genuine substitutable relationships.

Handle failures at the right boundary, preserve useful diagnostics, and guarantee cleanup for files and other disposable resources.

Write reusable type-safe code without falling back to object, casts, or duplicate methods for every data type.

Pass behavior as data, understand the method signature behind a lambda, and use Func, Action, and Predicate without hiding control flow.

Express filtering, projection, ordering, grouping, and aggregation as readable data queries while understanding deferred execution and repeated work.

Persist program data, build paths safely, choose whole-file or streaming APIs, and handle external storage as an unreliable boundary.

Keep a program responsive while waiting for I/O, understand Task as an eventual result, and avoid blocking, lost exceptions, and fake parallelism.

Move beyond one file: understand projects, namespaces, dependencies, configuration, and tests without creating architecture for its own sake.

Plan, build, test, and extend a file-backed console application that combines the complete beginner course without hiding the design decisions.

Model complex decisions with property, relational, list, and logical patterns while keeping domain rules exhaustive, readable, and easy to test.

Process contiguous data with Span and Memory, understand stack-only lifetime restrictions, and rent buffers without leaking pooled contents or ownership.

Design generic APIs with meaningful constraints, variance, static abstract members, and type-safe reuse without forcing callers through casts or reflection.

Inspect .NET metadata deliberately, define attributes with narrow semantics, cache reflection work, and avoid turning compile-time contracts into fragile string conventions.

Represent code as data with expression trees, distinguish delegates from translatable expressions, and build composable predicates without accidental client evaluation.

Compose asynchronous operations with cancellation and timeout policies, preserve exception context, and avoid blocking or abandoning work accidentally.

Protect shared state, choose synchronization primitives by invariant, use parallel loops only for measured CPU work, and recognize race conditions and deadlocks.

Build bounded asynchronous pipelines with Channel, apply backpressure, coordinate completion, and preserve failures across producer and consumer stages.

Read allocation evidence, understand generations and object lifetimes, reduce hot-path pressure carefully, and avoid pooling or caching that retains more memory.

Measure performance with representative benchmarks and profiles, account for warmup and noise, and connect optimization work to latency, throughput, or allocation goals.

Compose .NET applications through explicit dependencies, validate typed configuration, and produce structured logs without service-location or secret exposure.

Use HttpClientFactory, timeouts, cancellation, retries, circuit breakers, and idempotency deliberately while preserving diagnostics and connection reuse.

Design durable JSON contracts, distinguish transport models from domain models, evolve fields compatibly, and reject ambiguous or unsafe payloads.

Model relational persistence with EF Core, control query shape and tracking, protect transactions, and avoid N+1 queries or leaky IQueryable abstractions.

Organize use cases around domain rules and explicit ports, keep frameworks at boundaries, and apply layering or vertical slices without cargo-cult abstractions.

Design HTTP resources and Minimal API endpoints with explicit contracts, validation, status codes, dependency injection, cancellation, and OpenAPI documentation.

Reason about the ASP.NET Core middleware pipeline, authenticate identities, authorize policies, validate hostile input, and protect secrets, transport, and responses.

Test the real ASP.NET Core pipeline with WebApplicationFactory, controlled dependencies, realistic databases, authenticated clients, and stable assertions on public contracts.

Instrument services with logs, metrics, and traces, design meaningful health probes, publish deterministic containers, and deploy with safe configuration and rollback signals.

Design, implement, secure, test, observe, and package a production-style ASP.NET Core order API using the advanced course’s language and architecture skills.