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Learn C Programming

A free, interactive online C course. You write C on every lesson - variables, control flow, functions, pointers, memory management - with AI hints when something segfaults, and a free certificate when you finish.

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  • Beginner friendly
  • sparkles iconAI-assisted coding help
  • hint iconHands-on interactive lessons
  • volume On iconAudio narration on every lesson
  • quiz iconQuizzes to test your knowledge
  • certificate iconFree certificate of completion

Syllabus

3 sections4 projects187 lessons163 challenges1,042 quiz questions
  1. Section 1

    Fundamentals

    Start sectionStartExpandCollapse    Build a strong foundation with essential concepts and basic skills63 lessons78 challenges381 questions

    Introduction

    4 lessons326
    • 01C LanguageChallenge
    • 02Hello World!ChallengeQuiz
    • 03CommentsQuiz
    • 04Basic Program StructureChallengeQuiz

    Variables

    11 lessons1485
    • 01Data TypesChallengeQuiz
    • 02IntegerChallengeQuiz
    • 03Float - DoubleChallengeMasteryQuiz
    • 04CharactersChallengeQuiz
    • 05BooleansChallengeMasteryQuiz
    • 06ConstantsChallengeQuiz
    • 07printf BasicsChallengeQuiz
    • 08Variable Naming RulesChallengeQuiz
    • 09Type Casting Part 1ChallengeMasteryQuiz
    • 10Type Casting Part 2ChallengeQuiz
    • 11Recap ChallengeChallenge

    Operators

    9 lessons1161
    • 01Arithmetic OperatorsChallengeQuiz
    • 02Modulo OperatorChallengeMasteryQuiz
    • 03Increment/DecrementChallengeQuiz
    • 04Assignment OperatorsChallengeQuiz
    • 05Relational OperatorsChallengeQuiz
    • 06Logical Operators Part 1ChallengeQuiz
    • 07Logical Operators Part 2ChallengeQuiz
    • 08Logical Operators Part 3ChallengeMasteryQuiz
    • 09Recap ChallengeChallenge

    Control Flow

    7 lessons944
    • 01If StatementChallengeQuiz
    • 02If - ElseChallengeQuiz
    • 03Else-IfChallengeMasteryQuiz
    • 04Switch CaseChallengeMasteryQuiz
    • 05Ternary Conditional OperatorChallengeQuiz
    • 06Recap ChallengeChallenge
    • 07Nested If - ElseChallengeQuiz

    Input & Output

    5 lessons626
    • 01Format SpecifiersChallengeQuiz
    • 02scanf BasicsChallengeMasteryQuiz
    • 03Recap Challenge #1Challenge
    • 04Input ValidationChallengeQuiz
    • 05Recap Challenge #2Challenge

    Loops

    9 lessons1053
    • 01For LoopChallengeMasteryQuiz
    • 02While LoopChallengeQuiz
    • 03Do While LoopChallengeQuiz
    • 04BreakChallengeQuiz
    • 05ContinueChallengeQuiz
    • 06Recap Challenge #1Challenge
    • 07Nested LoopsChallengeMasteryQuiz
    • 08Infinite LoopsQuiz
    • 09Recap Challenge #2Challenge

    Functions

    7 lessons1039
    • 01Declare a FunctionChallengeQuiz
    • 02Return TypesChallengeMasteryQuiz
    • 03ParametersChallengeMasteryQuiz
    • 04Recap Challenge #1Challenge
    • 05Recursion BasicsChallengeMasteryQuiz
    • 06Function PrototypesChallengeQuiz
    • 07Recap Challenge #2Challenge

    Arrays

    8 lessons1247
    • 01Declaring ArraysChallengeQuiz
    • 02Accessing ElementsChallengeQuiz
    • 03Modifying ElementsChallengeMasteryQuiz
    • 04Multidimensional ArraysChallengeMasteryQuiz
    • 05Recap Challenge #1Challenge
    • 06Arrays as Function ArgumentsChallengeMasteryQuiz
    • 07Array AlgorithmsChallengeMasteryQuiz
    • 08Recap Challenge #2Challenge

    Final Challenges

    3 lessons3
    • 01GradesChallenge
    • 02PeaksChallenge
    • 03TVChallenge
  2. Section 2

    Logic & Flow

    Start sectionStartExpandCollapse    Master advanced C programming with a focus on data structures and flow control. Learn to work with complex arrays, collections, error handling, and time management.63 lessons52 challenges345 questions2 projects

    Pointers Fundamentals

    6 lessons540
    • 01What is a Pointer?Quiz
    • 02Declaring PointersChallengeQuiz
    • 03The Address-Of Operator (&)ChallengeQuiz
    • 04The Dereference Operator (*)ChallengeQuiz
    • 05NULL PointersChallengeQuiz
    • 06Recap: Pointer BasicsChallenge

    Pointers and Arrays

    5 lessons531
    • 01Array Names as PointersChallengeQuiz
    • 02Array Elements - PointersChallengeQuiz
    • 03Pointer ArithmeticChallengeQuiz
    • 04Comparing PointersChallengeQuiz
    • 05Recap: Pointer Array TraversalChallenge

    Character Arrays and Strings

    8 lessons858
    • 01Strings as char ArraysChallengeQuiz
    • 02The Null TerminatorChallengeQuiz
    • 03String Input with scanfChallengeQuiz
    • 04Using strlen()ChallengeQuiz
    • 05Using strcpy()ChallengeQuiz
    • 06Using strcat()ChallengeQuiz
    • 07Using strcmp()ChallengeQuiz
    • 08Recap: Basic String FunctionsChallenge

    Project: Simple Text Utility

    Project5 lessons1
    • 01Project OverviewChallenge
    • 02Counting CharactersProject
    • 03Counting VowelsProject
    • 04Convert to UppercaseProject
    • 05Final OutputProject

    Pointers and Functions

    6 lessons641
    • 01Pass-by-ValueChallengeQuiz
    • 02Passing Pointers to FunctionsChallengeQuiz
    • 03Modifying Vars via PointersChallengeQuiz
    • 04A Classic Example: SwapChallengeQuiz
    • 05Passing Arrays to FunctionsChallengeQuiz
    • 06Recap: Function Pointer ArgsChallenge

    Memory Management

    7 lessons652
    • 01Stack vs. Heap MemoryQuiz
    • 02Dynamic Allocation - malloc()ChallengeQuiz
    • 03Using sizeof() for AllocationChallengeQuiz
    • 04Checking Allocation FailureChallengeQuiz
    • 05Freeing Memory with free()ChallengeQuiz
    • 06Allocating with calloc()ChallengeQuiz
    • 07Recap: Dynamic ArrayChallenge

    Structures (structs)

    6 lessons540
    • 01What is a Struct?Quiz
    • 02Declaring a StructChallengeQuiz
    • 03Creating Struct VariablesChallengeQuiz
    • 04Accessing Struct MembersChallengeQuiz
    • 05Initializing StructsChallengeQuiz
    • 06Recap: Student Data StructChallenge

    Structs and Pointers

    6 lessons643
    • 01Pointers to StructsChallengeQuiz
    • 02The Arrow Operator (->)ChallengeQuiz
    • 03Passing Structs by ValueChallengeQuiz
    • 04Passing Struct PointersChallengeQuiz
    • 05Dynamic Allocation of StructsChallengeQuiz
    • 06Recap: Modifying Struct - PtrChallenge

    Project: Simple Contact Entry

    Project5 lessons1
    • 01Project: Define Contact StructChallenge
    • 02Function to Create a ContactProject
    • 03Function to Populate a ContactProject
    • 04Function to Display a ContactProject
    • 05Putting It All TogetherProject

    Enums and Typedef

    6 lessons640
    • 01enum for Named ConstantsChallengeQuiz
    • 02Declaring and Using EnumsChallengeQuiz
    • 03Enums in Switch StatementsChallengeQuiz
    • 04Using typedef for Type AliasesChallengeQuiz
    • 05typedef with StructsChallengeQuiz
    • 06Recap: Typedef & Enum PracticeChallenge

    Final Recap Challenges

    3 lessons3
    • 01Recap: Dynamic String ConcatChallenge
    • 02Recap: Array of StructsChallenge
    • 03Recap: Word Frequency CounterChallenge
  3. Section 3

    Object Oriented Programming

    Start sectionStartExpandCollapse    Discover how to organize code with classes, objects, and reusable structures61 lessons50 challenges316 questions2 projects

    Modular Programming Basics

    5 lessons433
    • 01Header FilesQuiz
    • 02Include GuardsChallengeQuiz
    • 03Source FilesChallengeQuiz
    • 04Static FunctionsChallengeQuiz
    • 05Recap: Modular CalculatorChallenge

    Objects and Methods

    6 lessons642
    • 01Structs as ObjectsChallengeQuiz
    • 02The 'Self' PointerChallengeQuiz
    • 03Const CorrectnessChallengeQuiz
    • 04Pointer vs ValueChallengeQuiz
    • 05Helper MethodsChallengeQuiz
    • 06Recap: Point ManagerChallenge

    Object Lifecycle

    5 lessons533
    • 01Constructor PatternChallengeQuiz
    • 02Destructor PatternChallengeQuiz
    • 03Stack InitializationChallengeQuiz
    • 04Deep CopyChallengeQuiz
    • 05Recap: String WrapperChallenge

    Encapsulation

    5 lessons435
    • 01Opaque Pointers ConceptQuiz
    • 02Defining Opaque StructsChallengeQuiz
    • 03Getters and SettersChallengeQuiz
    • 04Validation in SettersChallengeQuiz
    • 05Recap: Secret BoxChallenge

    Project: Simple Bank Account

    Project6 lessons1
    • 01Project SetupChallenge
    • 02Implementation of AccountProject
    • 03Deposit LogicProject
    • 04Withdraw LogicProject
    • 05Get BalanceProject
    • 06Project Finale: Main LoopProject

    Inheritance via Composition

    5 lessons531
    • 01Struct EmbeddingChallengeQuiz
    • 02The First Member RuleChallengeQuiz
    • 03Accessing Parent MembersChallengeQuiz
    • 04UpcastingChallengeQuiz
    • 05Recap: Shape HierarchyChallenge

    Function Pointers

    5 lessons534
    • 01Declaring Function PointersChallengeQuiz
    • 02Calling Function PointersChallengeQuiz
    • 03Typedef for Function PointersChallengeQuiz
    • 04Passing Functions as ArgumentsChallengeQuiz
    • 05Recap: Calculator DispatchChallenge

    Polymorphism

    6 lessons641
    • 01Function Pointers in StructsChallengeQuiz
    • 02Simulating MethodsChallengeQuiz
    • 03The Interface ConceptChallengeQuiz
    • 04Implementing InterfacesChallengeQuiz
    • 05Polymorphic IterationChallengeQuiz
    • 06Recap: GreeterChallenge

    Project: Shape Drawer

    Project5 lessons1
    • 01Project OverviewChallenge
    • 02Circle ImplementationProject
    • 03Rectangle ImplementationProject
    • 04Polymorphic UsageProject
    • 05Shape ContainerProject

    Generic Containers

    5 lessons534
    • 01Void Pointers RecapChallengeQuiz
    • 02Generic WrapperChallengeQuiz
    • 03Generic SwapChallengeQuiz
    • 04Generic CompareChallengeQuiz
    • 05Recap: Generic ArrayChallenge

    Design Patterns in C

    4 lessons425
    • 01Singleton PatternChallengeQuiz
    • 02Factory PatternChallengeQuiz
    • 03Iterator PatternChallengeQuiz
    • 04Recap: Logger FactoryChallenge

    Final Challenges

    4 lessons48
    • 01RPG CharacterChallenge
    • 02Dynamic String BuilderChallenge
    • 03Generic StackChallenge
    • 04Event SystemChallengeQuiz

C courses

Hands-on C courses, free to start in your browser.

Data Structures

Beginner Challenges - Practice Basic Concepts

Popular

Put your beginner coding knowledge to test and try to solve this programming challenges, use any language you want, Happy Coding!

certificate icon

Certificate on completion

  • 20
  • 20

Coding Problems

Popular

Put your programming problem solving skills to the test using the exercises with different difficulties in this course. Designed for coders with some prior knowledge of the basic syntax in any programming language.

certificate icon

Certificate on completion

  • 32
  • 31

Coding Problems: Volume 2

Put your programming problem solving skills to the test using the exercises with different difficulties in this course. Designed for coders with some prior knowledge of the basic syntax in any programming language. This course is an extension of the first Coding Problems

certificate icon

Certificate on completion

  • 25
  • 24

Stack - Data Structures Series #1

In this course, you will learn about the Stack data structure, create a Stack from zero using your preferred language, and practice coding challenges with it!

Data Structures
  • 13
  • 6
  • 1

Recursion Challenges - Master The Recursive Thinking

Recursion is an important concept in computer science and a very powerful tool in writing algorithms. In this course, you will use recursion to solve challenges from beginner to advanced. In the end, you will ace this topic.

certificate icon

Certificate on completion

  • 15
  • 15

Star Pattern Bootcamp

Put your programming problem solving skills to learn how to print star patterns range from simple to complex, involving different levels of nested loops, conditional statements, and mathematical calculations.

  • 30
  • 28
See all 29 C courses →

Why learn C with Coddy

  • Write and run real C code in your browser. No GCC install, no Makefile, no toolchain setup. Each exercise compiles your C program server-side and shows the output instantly.
  • C the way it's actually used: pointers and references, arrays, strings, structs, dynamic memory with malloc and free, file I/O. The C foundations every systems programmer needs.
  • AI hints help you read and fix C compiler errors and segfaults so the language feels approachable instead of cryptic from day one.
  • Free C programming certificate when you finish the course. A credible signal for systems, embedded, OS, and game-engine roles where C fluency is expected.

Frequently asked questions about learning C

Is C hard to learn?

C has a smaller feature set than most modern languages, but it makes you confront pointers and manual memory management early - which is why it has a reputation for being difficult. The course introduces those ideas one step at a time, with hands-on exercises after every concept, so the hard parts don't all hit at once.

Should I learn C or C++ first?

For embedded, OS-level, or low-level systems work, start with C - it's smaller and closer to the metal. For application development, game engines, or modern systems work, C++ is the more common choice and gives you a gentler ramp through classes before you have to manage memory by hand.

How long does it take to learn C programming?

C basics - variables, conditionals, loops, functions - take two to four weeks of daily practice. Becoming comfortable with pointers, structs, and dynamic memory usually takes another one to three months. Mastery (system-level code, performance work, large C codebases) is a multi-year arc.

Can I learn C programming online for free?

Yes. The interactive C course is free - full lessons, coding exercises, quizzes, and a certificate of completion. The C compiler runs server-side, so you don't need to install GCC, Clang, or any IDE locally to start writing C.

Do I need to install a C compiler to take this course?

No. Every C exercise compiles in a sandboxed environment and shows the output next to your code. There's no Makefile, no IDE, no toolchain to configure.

Do I get a certificate after the C programming course?

Yes. Finishing the C programming course gives you a free certificate of completion you can add to your resume or share on LinkedIn - useful alongside any systems-programming projects or GitHub repos you've built.
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