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Online C Compiler

Write, run, and share code snippets — no setup required.

main.c
Output
Click Run to see the output here.

Compile and run C online in your browser

This is a free online C playground and compiler. Write C code directly in your browser, hit Run, and watch gcc compile and execute your program in seconds — no local gcc, no clang, no make or CMake required. It's the fastest way to test a pointer trick, verify a struct layout, or work through a classic K&R exercise.

Under the hood, the editor uses the same engine as VS Code (C syntax highlighting, autocompletion, diagnostic squiggles), and your code compiles with gcc on Alpine Linux against musl libc with the full C99/C11 standard library available — <stdio.h>, <stdlib.h>, <string.h>, <math.h>, <time.h>, <stdint.h>. Whether you're debugging a segfault, testing a bit-manipulation trick, or prepping for a C interview, this online C compiler goes from idea to output in seconds.

What makes this C playground useful

  • Instant C compilation — write code, press Run, and see output from the online gcc compiler in seconds, no Makefile or CMake needed.
  • Full C syntax highlighting, header autocompletion, and clear gcc diagnostics — the same editor engine that powers VS Code.
  • Stdin input supported — scanf, getchar, fgets(buf, n, stdin) all read from the playground's input box, so you can test interactive and interview-style programs without scaffolding a project. No install — no gcc, clang, MinGW, or WSL.
  • gcc compiler on Alpine Linux — write C with pointers, structs, and the full C99/C11 standard library, then compile and run in one click.

What you can build in the C playground

  • Pointer arithmetic, arrays, and string manipulation — core C idioms you can step through with printf debugging.
  • Data structures by hand — linked lists, binary trees, hash tables — plus classic algorithms (sorting, BFS, DFS, recursion) the way C exposes memory layout.
  • Quick C experiments — test a format specifier, check a struct's sizeof, verify a bitmask, or confirm how an operator associates without spinning up a Makefile.

Online C compiler FAQ

Is the online C compiler free?
Yes. The online C playground is completely free — no sign-up, no gcc to install, no MinGW or WSL to configure. Open the page and compile.
Do I need gcc or a C compiler installed?
No install needed. You don't need gcc, clang, MinGW, or WSL on your machine — the online C compiler compiles your code with gcc on Alpine Linux and runs it in seconds.
Does the C playground work on mobile and Chromebooks?
Yes. The C playground runs on any modern browser — desktop, tablet, or mobile. Great for compiling C from a Chromebook, iPad, or school computer where you can't install a toolchain.
Does the online C compiler support scanf and stdin?
Yes. The playground has a stdin input box — scanf, getchar, and fgets(buf, n, stdin) all read your typed lines the same way they would when you run ./a.out locally and type at the terminal. Pointers and memory tricks that might segfault also run safely since the binary executes in a sandboxed Alpine container.
How do I learn C after trying the playground?
Edit the sample C code, press Run, and iterate. When you want structured practice, Coddy's interactive C course covers pointers, memory management, structs, and the standard library with hands-on exercises.