gcc 11.3.0

Online C Compiler & Editor

Name: myCompiler C
Author: myCompiler

myCompiler is a free online C compiler, editor and code runner that lets you write, run, and share C code directly in your browser. It works as your C playground, sandbox, fiddle, cloud compiler, and online REPL. No downloads, no installation needed. Just open the editor and start coding with syntax highlighting, autocomplete, and instant output.

Start coding in C How it works

27+ languages Used by 1M+ developers Free forever

main.c

#include <stdio.h>

int main() {
    int nums[] = {4, 2, 7, 1, 9};
    int n = sizeof(nums) / sizeof(nums[0]);
    int max = nums[0];

    for (int i = 1; i < n; i++) {
        if (nums[i] > max) max = nums[i];
    }

    printf("Max value: %d\n", max);
    return 0;
}

Output

Max value: 9

How to run C code online

Three steps to go from idea to running C code in this online playground. No account required.

Write your code

Open the C editor and start writing. The smart editor gives you syntax highlighting, autocomplete, and error detection as you type.

Click Run

Hit the Run button or press +Enter to run your C code on secure, sandboxed cloud servers.

See results

Output appears instantly in the integrated terminal. Errors and exceptions show up with clear, helpful messages.

Everything you need to code in C

A complete online C IDE and coding playground in your browser. Write, run, and share code without any setup.

Zero setup required

Start coding in seconds with this browser-based C interpreter. No downloads, no installations, no environment configuration. Open your browser, go to myCompiler, and start writing C code immediately.

Works on any device with a web browser. Desktop, laptop, tablet, phone, Chromebook. There is nothing to install and nothing to configure.

Feature-rich code editor

Write C with a professional-grade code editor built into your browser. Syntax highlighting colors your code for readability, making keywords, strings, and functions easy to distinguish at a glance.

Intelligent autocomplete suggests methods and properties as you type, and real-time error detection catches mistakes before you run your code.

Multi-file projects

Create and manage multiple files in a single project. Use the file sidebar to organize your code into modules, then import them across files just like in a desktop IDE.

Build modular applications with proper project structure. Each file is editable, and you can switch between them instantly.

Run code instantly

Click the Run button or press +Enter to execute your C code instantly. This online code runner displays output immediately in the integrated terminal panel. Your code runs on secure, sandboxed cloud servers and results appear in seconds.

Error messages and tracebacks are displayed clearly, making it easy to find and fix issues. The terminal supports ANSI colors for rich output formatting.

Ready to try it? Write and run your first C program in seconds.

Open C editor

C on myCompiler

myCompiler runs gcc 11.3.0, always up to date with the latest stable release. You get a full browser-based IDE with syntax highlighting, intelligent code completion, multi-file project support, a built-in terminal for real-time output, and standard input (stdin) for interactive programs. Write, compile, run, and debug C code on any device. Desktop, laptop, tablet, phone, Chromebook. Zero downloads, zero configuration, and no sign-up required. Save your programs with a unique URL and share them with anyone. You can also embed a working C editor on your own website.

Use this online C playground as a quick code executor for testing snippets, a coding sandbox for learning, or a cloud compiler for coding interview preparation. The editor includes dark mode for comfortable coding, keyboard shortcuts for faster workflows, and clear error messages with line numbers so you can debug quickly. Students use it for homework and practice. Teachers use it to share working examples. Developers use it to prototype ideas. myCompiler is beginner-friendly, fast, and completely free. It works in any modern web browser.

Start coding in C

C code examples

Common C patterns you can try in the online compiler. Each example is ready to run.

Hello World in C

main.c

#include <stdio.h>

int main() {
    printf("Hello, World!\n");
    return 0;
}

Variables and Data Types in C

main.c

#include <stdio.h>

int main() {
    char name[] = "Alice";
    int age = 30;
    float height = 5.6;
    printf("%s is %d years old\n", name, age);
    return 0;
}

If-Else Conditionals in C

main.c

#include <stdio.h>

int main() {
    int x = 10;
    if (x > 0) printf("Positive\n");
    else if (x == 0) printf("Zero\n");
    else printf("Negative\n");
    return 0;
}

For and While Loops in C

main.c

#include <stdio.h>

int main() {
    for (int i = 0; i < 5; i++)
        printf("Count: %d\n", i);

    int total = 0;
    while (total < 10) total += 3;
    printf("Total: %d\n", total);
    return 0;
}

Functions in C

main.c

#include <stdio.h>

void greet(const char *name) {
    printf("Hello, %s!\n", name);
}

int main() {
    greet("Alice");
    greet("Bob");
    return 0;
}

Arrays and Collections in C

main.c

#include <stdio.h>

int main() {
    int nums[] = {1, 2, 3, 4, 5};
    int sum = 0;
    for (int i = 0; i < 5; i++) sum += nums[i];
    printf("Sum: %d\n", sum);
    return 0;
}

Structs in C

main.c

#include <stdio.h>

typedef struct {
    char name[50];
    int age;
} Person;

int main() {
    Person alice = {"Alice", 30};
    printf("%s is %d\n", alice.name, alice.age);
    return 0;
}

Error Handling in C

main.c

#include <stdio.h>
#include <errno.h>
#include <string.h>

int main() {
    FILE *f = fopen("nonexistent.txt", "r");
    if (!f) printf("Error: %s\n", strerror(errno));
    else fclose(f);
    return 0;
}

File I/O in C

main.c

#include <stdio.h>

int main() {
    FILE *f = fopen("output.txt", "w");
    fprintf(f, "Hello, File!");
    fclose(f);
    f = fopen("output.txt", "r");
    char buf[100];
    fgets(buf, sizeof(buf), f);
    printf("%s\n", buf);
    fclose(f);
    return 0;
}

Pointers in C

main.c

#include <stdio.h>

void swap(int *a, int *b) {
    int temp = *a; *a = *b; *b = temp;
}

int main() {
    int x = 5, y = 10;
    swap(&x, &y);
    printf("x=%d, y=%d\n", x, y);
    return 0;
}

Try these examples in the editor

How to take input in C online

myCompiler supports standard input (stdin) for C programs. Use C's standard input functions to read user input. Enter your input data in the stdin panel before running your program.

This works for both single-line and multi-line input. You can read strings and convert to numbers using the language's built-in I/O functions.

Try it yourself

main.c stdin supported

#include <stdio.h>

int main() {
    char name[50];
    int age;

    scanf("%s", name);
    scanf("%d", &age);

    printf("Hello %s!\n", name);
    printf("You'll be %d next year.\n", age + 1);
    return 0;
}

stdin

Alice
25

Output

Hello Alice!
You'll be 26 next year.

No setup, no sign-up. Start writing C code right now.

Start coding now

Getting started with C online

You can start writing and running C code right now without installing anything. Type your code, and click Run. This free C code runner executes your program instantly and displays the output in the terminal panel below the editor. Open the C online editor, type your code, and click Run.

If you're new to C, use this online C playground to start with the basics like variables, data types, conditionals, and loops. The code examples above cover all the fundamentals you need to get started. Each example can be copied into the sandbox and run immediately. No setup, no configuration.

As you progress, try creating multi-file projects, using libraries, and sharing your programs with others via URL. Sign up for a free account to save your work and build a personal library of programs. myCompiler works as a full online C IDE right in your browser.

Who uses myCompiler

Whether you're learning to code, preparing for interviews, or prototyping ideas, myCompiler is built for you.

Students & Learners

Practice exercises, complete homework assignments, and experiment with code without installing anything on school or personal computers.

Teachers & Educators

Share code examples with students via unique URLs. Embed the compiler in course materials so students can run examples directly in the browser.

Interview Candidates

Practice coding interview problems, test algorithms, and verify solutions quickly during preparation for technical interviews.

Professional Developers

Quickly prototype ideas, test code snippets, or try out a library without setting up a local environment. Great for quick experiments.

Content Creators & Bloggers

Embed interactive examples in blog posts, tutorials, and documentation so readers can run code without leaving the page.

Teams & Collaborators

Share code snippets with colleagues via URLs. Others can view, run, and fork your code to build on your work.

myCompiler vs. local IDE

Why use an online C compiler instead of installing one locally?

Feature	myCompiler	Local IDE
Setup time	Instant	Minutes to hours
Installation	None required	C + IDE required
Device support	Any browser	Desktop only
Sharing code	One-click URL	Manual (file, git, etc.)
Languages	27+ in one place	One at a time
Cost	Free forever	Free to $$$
Works on Chromebook	Yes	Limited

What is C?

C is a general-purpose, procedural programming language developed by Dennis Ritchie at Bell Labs between 1969 and 1973. It is one of the most influential programming languages ever created, the Unix operating system was rewritten in C, and nearly every modern operating system kernel, from Linux to macOS to Windows, is written substantially in C.

C gives programmers direct control over memory through pointers and manual memory management with malloc and free. This low-level access makes C exceptionally fast and portable, a C program compiled for one platform can be recompiled and run on almost any hardware. C also served as the foundation for C++, Objective-C, Java, C#, and many other languages.

What is C used for?

C is used for operating systems (Linux, Windows kernel, macOS kernel), embedded systems and firmware in microcontrollers and IoT devices, device drivers and hardware interfaces, databases (SQLite, PostgreSQL), compilers and interpreters (the Python interpreter CPython is written in C), and high-performance computing. Anywhere raw performance and hardware access matter, C is used.

C for beginners

C is not the easiest language to start with, you must manage memory manually and understand pointers, but learning C builds a deep understanding of how computers work. Many computer science programs teach C as a foundational language because it exposes concepts like memory allocation, stack vs. heap, and pointer arithmetic that higher-level languages abstract away. Use myCompiler's online C compiler (powered by GCC) to learn C without installing a development environment.

C vs other languages

Compared to C++, C is simpler and lacks object-oriented features, templates, and the STL, but this simplicity makes C easier to reason about for low-level system code. Compared to Rust, C has no memory safety guarantees, making buffer overflows and use-after-free bugs possible, but C has a much smaller learning curve and a 50-year head start on tooling and libraries. Compared to Python, C is dramatically faster but far harder to write and debug.

Why use an online C compiler?

An online C compiler, also called a C sandbox or C code runner, lets you compile and run C programs directly in your browser without installing GCC or any compiler. This is useful for practicing data structures, algorithms, pointer manipulation, and systems programming concepts for courses, coding interviews, and competitive programming, all without local setup.

myCompiler's online C compiler uses GCC, supporting C11 and C17 standards with standard headers like stdio.h, stdlib.h, string.h, and math.h. You can provide stdin input, write multi-file programs, save and share your code, all free.

Why is C so popular?

C has remained consistently popular for over 50 years because it is irreplaceable for systems programming. No other language combines C's combination of portability, performance, and hardware access. The entire computing infrastructure, operating systems, embedded devices, databases, compilers, runs on C. Understanding C is foundational to understanding modern computing, which is why it ranks in the top 2 on the TIOBE index year after year.

C career opportunities

C expertise opens doors to embedded systems engineer, systems programmer, firmware developer, kernel developer, and performance engineer roles. Industries including aerospace, automotive, telecommunications, and defense rely heavily on C. While C jobs are more specialized than web development roles, they are well-compensated and the skills are fundamental to computer science education and system-level work.

Try C online Free · No sign-up needed

Keyboard shortcuts

Code faster with these keyboard shortcuts in the myCompiler editor.

Run code

+ Enter

Save program

+ S

Toggle comment

+ /

Indent line

Tab

Unindent line

Shift + Tab

Undo

+ Z

Select next occurrence

+ D

Find & replace

+ H

Embed the C compiler on your website

Add an interactive C compiler to your website, blog, or learning platform. Readers can write and run C code directly on your page without leaving it.

Perfect for technical tutorials, coding courses, documentation, and educational content. Save a program on myCompiler and use the embed link to add it to any webpage.

Embedded C compiler, editor and code runner

HTML

<iframe
src="https://www.mycompiler.io
    /embed/c"
width="100%"
height="400"
frameborder="0">
</iframe>

Why developers choose myCompiler

A full-featured online IDE for C and 27+ other programming languages.

27+ Languages

Python, JavaScript, Java, C++, Rust, Go, TypeScript, C#, and many more. All compilers and interpreters in one place. Switch languages instantly.

Dark & Light Mode

Switch between light and dark themes with one click. Code comfortably in any lighting condition, day or night.

Mobile Friendly

Fully responsive editor optimized for phones, tablets, and Chromebooks. Code on any device with a web browser. No app download needed.

Save & Share Code

Save programs to your account, share via unique URLs, and let others view, fork, and run your code. Great for collaboration and code reviews.

Tags & Organization

Organize your saved programs with tags and find them quickly with search and filters. Build a personal library of code snippets and solutions.

No Account Required

Start writing and running code immediately. No sign-up, no email, no credit card. Create a free account later only if you want to save your work.

Explore more programming languages

myCompiler supports 27+ languages. Switch between them anytime. All free, all in one place.

View all 27+ languages

Frequently asked questions

Common questions about using the online C compiler, playground, and code runner.

Yes! myCompiler is completely free for all supported languages including C. There are no subscriptions, no premium tiers, and no hidden costs. Every feature is available at no charge.

myCompiler keeps its C environment up to date. You can see the exact version on the language details section of this page. We regularly update all language runtimes to their latest stable versions.

myCompiler uses GCC (GNU Compiler Collection) to compile and run your C code. GCC supports the latest C standards and produces optimized output for a wide range of programs.

Simply open the C editor, write or paste your code, and click the Run button. Your code will be executed on our servers and the output will appear in the terminal panel within seconds.

Yes. Click Save to store your program. You will receive a unique URL that you can share with anyone. Recipients can view, fork, and run your code.

Yes. myCompiler supports multi-file projects. You can create, rename, and delete files in the sidebar. This lets you organize your C code just like in a local IDE.

Yes. All code runs in isolated containers on our servers. Each execution gets its own sandboxed environment that is destroyed after completion. Your code cannot affect other users or our infrastructure.

Yes. myCompiler has a responsive design optimized for phones and tablets. You can write and run C code on the go. The mobile interface uses tabs for switching between the editor, output, and file panels.

Yes. Click the Input tab in the bottom panel, type or paste your input data, then click Run. Your program will read from the input you provided.

Execution is fast. Code runs on our optimized cloud infrastructure and output typically appears within seconds. Execution time depends on the complexity of your program.

Yes. myCompiler provides an embed feature. You can copy an iframe snippet and paste it into your website, blog, or documentation. Visitors can edit and run code directly on your page.

myCompiler supports common editor shortcuts including Run (Ctrl/Cmd+Enter), Save (Ctrl/Cmd+S), Find (Ctrl/Cmd+F), and more. See the keyboard shortcuts section on this page for the full list.

No. myCompiler requires an internet connection because code is compiled and executed on our cloud servers. The editor itself loads in your browser, but running code requires connectivity.

myCompiler offers a fast, free, zero-setup environment with a modern code editor, multi-file support, dark mode, and instant sharing. It is ideal for learning, prototyping, interviews, and sharing code examples.

Yes. myCompiler is great for practicing algorithms and coding problems. You can write C code, provide custom input, and test your solutions instantly. Save your work and come back to it anytime.

Use print statements or console output to trace your program's behavior. myCompiler shows all standard output and error messages in the terminal panel. Error messages include line numbers to help you locate issues.

Ready to write C code?

Open the free C playground and start coding immediately. No downloads, no account required.

Start coding in C

Free · No sign-up required · gcc 11.3.0