Multithreaded TCP Trivia Game

Bachelor's Degree Project — Computer Networks Course (Reti Informatiche / Reti di Calcolatori)

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Overview

This repository contains the implementation of a Multithreaded Client-Server Trivia Quiz Game written in C using POSIX Sockets and POSIX Threads (pthreads).

The project demonstrates fundamental networking and operating system concepts, including TCP/IP socket communication, concurrent client handling via thread pooling/spawning, dynamic memory allocation with linked lists, and thread synchronization using mutexes.

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Key Features

• TCP Client-Server Architecture: Reliable connection-oriented communication over TCP (default port 3456).
• Concurrent Multi-Client Handling: Spawns a dedicated POSIX thread (pthread_create) for each incoming client connection, allowing multiple players to connect and play simultaneously without blocking the main server loop.
• Dynamic File-Based Trivia Loading: Automatically loads quiz categories, questions, and answers from text files into dynamically allocated singly linked lists at server startup.
• Thread-Safe State Management: Utilizes POSIX mutexes (pthread_mutex_t) to prevent race conditions when accessing shared resources, such as global player lists and score leaderboards.
• Player & Score Tracking: Comprehensive data structures to track player sessions, active/completed themes, and dynamic leaderboard rankings.

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Project Structure

Computer-Network-Project/
├── bin/                 # Compiled object files (*.o)
├── const/
│   └── const.h          # Global constants, macros, and configuration paths
├── include/
│   ├── all.h            # Standard library and POSIX networking headers
│   ├── client.h         # Client-specific definitions
│   ├── serverlib.h      # Data structures and server library prototypes
│   └── serverlib.c      # Implementation of file loading, linked lists, and game logic
├── src/
│   ├── client.c         # Client application entry point
│   └── server.c         # Server application entry point and connection listener
├── txt/                 # Quiz database (categories, questions, and answers)
│   ├── temi.txt         # List of available trivia themes
│   ├── domande1.txt     # Questions for Theme 1
│   ├── risposte1.txt    # Answers for Theme 1
│   ├── domande2.txt     # Questions for Theme 2
│   └── risposte2.txt    # Answers for Theme 2
├── makefile             # Build automation script
└── README.md            # Project documentation

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Architecture & Data Structures

The application relies on several core data structures defined in include/serverlib.h:

1. THEME (struct theme)

Represents a trivia category.

• name: Title of the category (loaded from temi.txt).
• NUM_DOMANDE: Number of questions in the category.
• lista_domande & lista_risposte: Singly linked lists (NODE*) containing the questions and corresponding answers.
• mutex: Dedicated mutex to ensure thread-safe score updates and leaderboard access for the theme.

2. PLAYER (struct player)

Represents a connected user session.

• name: Player username (up to NAME_MAX characters).
• active: Boolean flag indicating if the player is currently connected.
• temi_iniziati & temi_finiti: Boolean tracking arrays for theme progress.
• next: Pointer to the next player in the global connected players list.

3. NODE (struct node)

A dynamic linked list node used for storing variable-length quiz content in memory without hardcoded array limits.

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Getting Started

Prerequisites

To compile and run this project, you need a POSIX-compatible environment (Linux, macOS, or Windows via WSL/MSYS2) with:

• GCC (GNU Compiler Collection)
• Make
• POSIX Threads & Sockets support

Compilation

A makefile is provided for easy build automation. Open your terminal in the project root directory and run:

# Compile both server and client executables
make

# Or compile individually:
make server
make client

To clean up compiled binaries and object files:

make cls

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Running the Application

1. Start the Server

Start the server first. It will bind to 127.0.0.1:3456, load the trivia questions from the txt/ directory into memory, and begin listening for client connections:

./server

Expected output:

Server in ascolto

2. Start the Client(s)

In a separate terminal window (or multiple windows for concurrent players), launch the client:

./client

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