Hands-On: C for Intermediate Engineers

Once pointers, malloc and free, structs, linked lists and function pointers are familiar, the next C you write is often a checksum, a binary decoder, a hash table or an allocator. Each depends on rules a level below the beginner material: unsigned arithmetic wraps, the compiler pads between struct fields, a format’s byte order may differ from the machine’s, and a container for any element type has to be built from void * and an element size.

This hands-on course has 49 exercises, and every one runs in your browser without installing anything. Every lesson ends with C code for you to write, which tests then run and check. The code is C17 as clang compiles it. Fixed-width integers come first: wraparound in a 16-bit checksum, floor division with negative operands and an exact overflow check when parsing a uint64_t. Struct layout covers padding, offsetof, flexible array members and bit-fields, and binary formats cover both byte orders, a bounds-checked read cursor, LEB128 and a table-driven CRC-32. In generic code with void * you write a growable array, a stable merge sort and intrusive lists with container_of. Hash tables (chaining, linear probing, tombstones, rehashing) and binary search trees and heaps follow, ending with top-k selection on a bounded min-heap. Later chapters build custom allocators such as a bump arena and a fixed-size pool, work through macros, _Generic and variadic functions, and parse text, from UTF-8 validation and quoted CSV fields to a recursive-descent expression evaluator. The course ends with opaque types behind a header and two capstones, an LRU cache and a stack-based bytecode interpreter.

It suits engineers who have finished C for Beginners, or who already write C with pointers, dynamic memory, structs and function pointers, and want practice with the memory layout, byte-level encoding and data structures that larger C programs are built on.