The C Guide

By Flavio Copes

Learn C programming from scratch: variables, pointers, arrays, strings, structures, and the preprocessor. A guided path through the C tutorials on this site.

C is one of the most influential programming languages ever created.

It powers operating systems, databases, embedded devices, and the interpreters and runtimes of most other languages. Learn C and you understand how software actually talks to memory and hardware.

C is also remarkably stable. The language you learn today is essentially the language that has run the world for decades. That makes these tutorials solid ground: the fundamentals don’t move.

This page is your map to the C content on this site, organized as a learning path.

Where to start

Follow these in order and you’ll cover the core of the language:

• Introduction to the C Programming Language sets the stage, with your first program
• C Variables and types covers how data is stored
• C Operators for math, comparison, and logic
• C Conditionals with if and switch
• How to work with loops in C covers for, while, and do while
• Introduction to C Functions to organize your code
• Introduction to C Pointers is the topic that defines C. Take your time here.

Arrays and strings

In C, strings are arrays of characters, so these two topics go together:

• Introduction to C Arrays
• How to determine the length of an array in C
• Looping through an array with C
• Introduction to C Strings
• How to find the length of a string in C
• How to return a string from a C function
• Double quotes vs single quotes in C
• How to check a character value in C

Types, scope, and structure

Once you’re comfortable with the basics, these round out your understanding of how C programs are built:

• C Constants
• Booleans in C
• How to use NULL in C
• C Enumerated Types
• C Structures
• The typedef keyword in C
• Scope of variables in C
• C Global Variables
• Static variables in C
• Can you nest functions in C?

Input, output, and the toolchain

C programs talk to the outside world through standard I/O, and the preprocessor and header files hold everything together:

• Basic I/O concepts in C
• C conversion specifiers and modifiers
• Print the percentage character with printf() in C
• How to access the command line parameters in C
• C Header Files
• The C Preprocessor
• Fix the C ‘implicitly declaring library function’ warning

Go deeper

I collected all of this material, expanded and organized, in the free C Handbook. You can download it as PDF or EPUB and read it offline, cover to cover.

All posts on this topic are in the C tag archive.

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