C From The Ground Up

Read it online

A progressive C learning workbook from basics to systems programming. Each lesson is a small, readable program with the explanation in the comments and the code inline. This is not a polished application suite. It is a progression of lessons, exercises, and a few larger workbook-style projects.

The book is organized into five progressive parts:

• Part 1: The Beginner Path -- Core language fundamentals from Hello World through strings
• Part 2: The Intermediate Path -- Pointers, structs, dynamic memory, file I/O, and command-line arguments
• Part 3: The Advanced Path -- Projects and deeper topics including function pointers, recursion, linked lists, bit manipulation, and a line-based text editor
• Part 4: The Expert Path -- Systems programming with sockets, process management, hash tables, and multithreading
• Part 5: Expert Systems -- Multi-file projects, external libraries, terminal UI with ncurses, data parsing, and a capstone text adventure

Most lessons are single-file programs. Pick one .c file, compile it, and run it:

cc -Wall -Wextra -std=c23 \
  "Part 1 - The Beginner Path_ Core Concepts/1_hello_world.c" \
  -o /tmp/1_hello_world

/tmp/1_hello_world

If your compiler does not support -std=c23 yet, use -std=c17.

Lesson 31 is the exception: it is intentionally split across multiple files and built with its local Makefile.

make -C "Part 5 - Expert Systems & Application Development/31_make_files_for_multi_file_projects"

• The repo-level verification baseline prefers -std=c23 and falls back to -std=c17 when a compiler does not yet accept C23.
• Most lessons compile with cc -Wall -Wextra -Wpedantic -Wstrict-prototypes -std=c23 lesson.c -o lesson_name.
• Lessons 26 through 30 use POSIX or Unix-style APIs such as sockets, fork, waitpid, unistd.h, and pthread.
• Lesson 30 needs -pthread.
• Lesson 32 needs -lm.
• Lessons 33 and 35 need -lncurses or -lncursesw, depending on your system, so they are easiest to run on Unix-like systems or inside WSL on Windows.
• Several lessons expect runtime input or data files. Read the lesson comments before running them.

mdbook build
mdbook serve --open

The supported verification flow is:

mdbook build
CC=clang sh scripts/smoke_check.sh
CC=gcc sh scripts/smoke_check.sh

If your local GCC is versioned, use that compiler name instead, for example CC=gcc-15 sh scripts/smoke_check.sh.

GitHub Actions mirrors that verification path: .github/workflows/verify.yml runs mdbook build plus the smoke check under both Clang and GCC on pushes and pull requests.

This project is licensed under the MIT License. See LICENSE.