OneCompiler
C

C

Backend

C is the language behind operating systems, embedded devices and just about everything close to the hardware. This workspace comes with GCC installed, so you can compile and run a C program from the terminal with no toolchain to set up.

What's included

Compile and run from the terminal

GCC is installed and ready. Compile main.c with gcc main.c, then run the produced binary with ./a.out.

Real VS Code

The full cloud editor with an integrated terminal, the C/C++ extensions and a build-and-debug config in the .vscode folder.

Git ready

Clone, commit and push from the terminal, or connect a GitHub repo whenever you're ready.

Fast cold start

Boots in about a minute, with the compiler already in place so there's nothing to install first.

Tech stack

CGCClldbVS Code

What is C?

C is a compiled, general-purpose language that sits close to the hardware. It gives you direct control over memory and produces fast, small binaries, which is why it's still the language of choice for operating system kernels, embedded firmware and performance-critical code.

This workspace is a minimal C starter. It ships a single main.c that prints a greeting, so you have a program that compiles and runs from the start and a clean base for learning the language or working through exercises.

What's inside this workspace

The starter is one file, main.c, with a standard main function that prints Hello, World! using printf. GCC is already installed, so there's nothing to configure before you compile.

The .vscode folder includes a build task and an lldb launch config, which means you can build and debug from the editor as well as the terminal. It's a deliberately small setup so you can focus on the code.

Building and running

Open the terminal and compile with gcc main.c. By default that produces an executable named a.out, which you run with ./a.out. If you'd rather name the output, pass -o, for example gcc main.c -o app and then ./app.

To debug, use the build-and-debug config in the .vscode folder. It compiles the active file with debug symbols and launches it under lldb, so you can set breakpoints and step through your C code.

What you can build

Console programs, algorithm and data-structure practice, command-line tools, or experiments with pointers and memory. Split your code across multiple .c files and compile them together as the project grows, or add a Makefile once you want a repeatable build.

Frequently asked questions

How do I compile and run my C program?

Open the terminal and run gcc main.c to compile. That produces a.out by default, which you run with ./a.out. Use gcc main.c -o app if you'd prefer to choose the output name.

Which compiler is installed?

GCC. The README compiles with gcc, and the editor's build task is set up so you can also build the active file from the Run and Debug panel.

Can I debug C here?

Yes. The .vscode folder ships a build-and-debug config that compiles with debug symbols and launches under lldb. Set breakpoints in main.c and start it to step through your code.

Does this run a web server I can preview?

No, this template is a console program that prints to the terminal. There's no browser preview, since C programs here write their output to standard output.

Can I split my code across multiple files?

Yes. Add more .c and header files in the workspace and compile them together, for example gcc main.c utils.c -o app. For a bigger project, add a Makefile so the build is one command.

Is it free?

C runs on a paid Studio plan. Templates that are free to launch are marked as such, and you can upgrade from the pricing page to use this one.

Related templates

C online Studio — cloud C workspace | OneCompiler