The C++ Online Compiler is a full-stack, web-based development environment that allows users to write, compile, and execute C++ code directly within their browser. Built entirely from scratch, it removes the friction of local compiler setups by providing a seamless, real-time coding experience with instant output feedback and isolated execution.
Write C++ code and execute it instantly with results streamed directly to the browser.
Captures and cleanly displays both standard output (stdout) and compilation/runtime errors (stderr).
Executes user-submitted code securely utilizing Node.js child processes.
Uses the fs module to handle the creation and cleanup of temporary .cpp files on the server automatically.
A responsive, developer-friendly UI built with React.
The React frontend acts as the user interface, capturing code input and sending it to the backend via a REST API payload.
Upon receiving the request, the Express backend uses the fs module to write the raw string into a temporary .cpp file on the server.
The child_process module is used to spawn a system shell command. It first runs the compiler (like g++) on the .cpp file. If successful, it executes the resulting binary file.
The backend listens to the child process's data streams, captures the output or compilation errors, and sends it back to the React frontend as a structured JSON response.
Wrap the execution layer in isolated, ephemeral Docker containers to provide strict security limits on memory, CPU, and network access to prevent malicious code execution.
Upgrade the code input area with the Monaco Editor (the engine behind VS Code) to provide syntax highlighting, line numbers, and intelligent auto-completion.
Implement strict timeout rules on the child processes to automatically kill programs that enter infinite loops, preventing server resource exhaustion.