JustRunThis — Local Runner for Competitive Programming.

Figure 1. JustRunThis Qt Widgets desktop application.

Overview

JustRunThis is a Qt Widgets desktop application that provides a local runner for competitive-programming C++ snippets — no internet required. It lets you open any folder as a workspace, browse .cpp files in a left-panel folder tree, paste sample stdin from platforms like Codeforces, and compile and execute with a single click. The compiler output and program stdout/stderr are displayed together in a monospaced output panel. A 5-second execution timeout guards against infinite loops, and elapsed time is reported in the status label.

Features & Architecture

The app is built with C++17 and Qt 6 Widgets, compiled via CMake + Ninja. It invokes g++ -std=c++17 -O2 -Wall as a subprocess through CppRunner, which also manages the run subprocess and enforces the timeout. Compiled binaries are cached in the system's local app-data directory (%LOCALAPPDATA%\justrunthis\ on Windows, ~/.cache/justrunthis/ on Linux) and are never written next to source files. The project layout separates UI logic (MainWindow) from the build/run engine (CppRunner), and supports both Windows (MinGW 13 / Qt 6) and Ubuntu/Debian out of the box.