A robust command-line chat application written in C that supports multiple concurrent users, chat rooms, private messaging, and more.

• Added chat rooms functionality with lobby system
• Implemented room management (create, join, leave)
• Added automatic room cleanup when empty
• Enhanced private messaging system
• Added better buffer management and security
• Fixed various memory leaks and bugs

• Initial release
• Basic chat functionality
• Multiple client support
• Username identification
• Basic command system

• 🚀 Multi-client support (up to 10 simultaneous connections)
• 👤 Username identification and nickname changes
• 🏠 Multiple chat rooms with management
  • Default lobby system
  • Create custom rooms
  • Join/leave functionality
  • Automatic room cleanup
• 💬 Private messaging system
• 🕒 Message timestamps
• 📢 Join/Leave notifications
• 🔄 Automatic connection management
• ⚠️ Comprehensive error handling
• 🎨 System messages in a different format
• 🔒 Buffer overflow protection

To compile and run this chat application, you need:

• GCC compiler
• UNIX-like operating system (Linux, macOS, etc.)
• Basic knowledge of terminal/command line

1. Clone the repository:

git clone https://github.com/yourusername/c-chat-app.git
cd c-chat-app

2. Build the application using the provided build script:

./build.sh

Or compile manually:

gcc -Wall -Wextra chat-server.c -o chat-server
gcc -Wall -Wextra chat-client.c -o chat-client

1. Start the chat server:

./chat-server

The server will start listening on port 9340.

1. In a new terminal window, start a chat client:

./chat-client

2. Enter your username when prompted.

3. You will automatically join the lobby.

• /help - Show available commands
• /list - List all connected users
• /whois <username> - Show information about a user
• /nick <new_name> - Change your nickname
• /msg <user> <message> - Send private message
• /rooms - List available chat rooms
• /create <room> - Create a new chat room
• /join <room> - Join a chat room
• /leave - Leave current room

• All users automatically join the lobby upon connection
• The lobby cannot be deleted
• Users can chat in the lobby like any other room

• Created using /create <room_name>
• Automatically deleted when empty
• Maximum of 5 rooms at once (including lobby)
• Room creator automatically joins their created room

Messages appear in the following formats:

• Regular room messages:

[2024-03-12 14:30:45] [Room] John: Hello everyone!

• System messages:

[2024-03-12 14:30:45] SYSTEM: John has joined the chat
[2024-03-12 14:31:20] SYSTEM: Room Gaming has been closed (no active users)

• Private messages:

[2024-03-12 14:30:45] [PM from Alice]: Hey there!
[2024-03-12 14:30:45] [PM to Bob]: How are you?

The application uses:

• TCP sockets for communication
• Poll for handling multiple clients
• POSIX-compliant C code
• System V networking primitives
• Dynamic memory management for rooms
• Secure buffer handling

• Protected against buffer overflows
• Secure string handling
• Memory leak prevention
• Proper error handling
• Input validation

• Maximum of 10 concurrent users
• Maximum of 5 chat rooms (including lobby)
• Username length limited to 31 characters
• Message length limited to 511 characters
• Local network usage only (can be modified for internet use)
• No message persistence (messages are not saved)

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

This project is licensed under the MIT License - see the LICENSE file for details.

• Inspired by classic UNIX chat systems
• Built with modern error handling practices
• Designed for educational purposes

Linkedin Profile - @rudokir

Project Link: https://github.com/rudokir/c-chat-room