PolyChat
PolyChat is a cross-platform LAN chat application built with Qt, designed for classroom communication between teachers and students over a local network. It addresses common issues such as small projector text, file distribution difficulties, and repeated questioning by providing instant messaging within closed school networks. Users log in by simply providing their name and class number, then can create or join multiple group chats to exchange messages and files. Additional features include editable text formatting, saving chat content as files, and clearing chat history. The software uses a three-tier architecture separating the user interface, business logic, and data access layers. Messaging is implemented over UDP with broadcast on a specific port using Qt's signal-slot mechanism, while file transfer uses TCP for reliable transmission. The project includes unit testing with QTest and integration, system, and end-to-end testing. CI/CD pipelines are configured via GitHub Actions to automatically build and