This is a free C book and it can be downloaded in pdf and html formats. The book contents are Style and Program Organization, File Basics, Comments, and Program Headings, Variable Names, Statement Formatting, Statement Details, Preprocessor, Directory Organization and Makefile Style, User-Friendly Programming and Rules.

The C Book

This is the online version of The C Book, second edition. The book contents are Introduction, Variables & arithmetic, Control flow, Functions, Arrays & pointers, Structures, Preprocessor, Specialized areas, Libraries, Complete Programs and Answers.

Numerical Recipes in C

Numerical Recipes in C book can be accessed as individual chapters in pdf format.

 

Writing Bug-Free C Code

This free C book is online. Chapters are Understand Why Bugs Exist, Know Your Environment, Rock-Solid Base, The Class Methodology, A New Heap Manager, Designing Modules, General Tips, Style Guide.