The purpose of this assignment is to write a standalone UNIX application that performs some useful or entertaining task. It should make use of many (but probably not all) of the various system calls, libraries, and other UNIX/Linux features (from text book ""Beginning Linux Programming, 4th edition").

The source code for this assignment will have to be the right size: it should be more simple than, say, "echo", but not as involved as, say "apache". 

Assignment Writeup 
Before writing code, a write-up of the assignment must be completed (Think of this as a mini-"Specifications" document.) It should have three parts: 
1. The first should be titled "Description" and contain a paragraph describing in English what the program is and what it does 
2. The second part should be titled "Use Case" and contain a description of how a user might normally use the application and test the major features. When the time comes for me to grade your project, I will sit and watch you perform the use case you have described on your application. 
3. The third (and last) part should be titled "Feature Breakdown" and is a delineation of each major area of functionality supported by the program. 

Example of the Write-up 

Description
For my assignment, I am going to write an interactive chat program called laim (Limited Application for Instant Messaging) laim allows two users to bi-directionally "chat" over TCP/IP similar to AIM, Yahoo Messenger and Linux talk.

Use Case
User1 opens a terminal window and types laim. If this is the first time the user has run laim they will be prompted for a nickname. The user will then be placed in WAITING status until a connection is made. 
User2 executes laim as above. User2 then initiate a conversation with User2 or (User1 initiates with User2) by opening a connection and specifying the other party's Linux username and optionally the hostname if the person is on a different machine. The other party then accepts or rejects the request. If the other party accepts, User1 and User2 may send messages to one another until one of them terminates the connection.
If User3 attempts to connect with either User1 or User2 during their connection, User3 will receive a BUSY indication.

Feature Breakdown
• Command line parsing using getopt() 
• Interprocess Communication to establish connections and to manage communication 
• TCP/IP networking 
• Bidirectional, non-blocking communication using select() 
• SQLite3 SQL to save and retrieve user information in ~/.laim_profile 
• Screen I/O and terminal management with multiple virtual screens

Requirements
• Program must do something useful for the user. 
• Program must be written in C or C++ and execute on our Ubuntu server. 
• Program must substantially conform to your write-up. 
• Code should be well-structured, adequately commented and handle common errors appropriately. Source code should be processed with a source code beautifier in the K&R style with tabs for indenting and tabstops set to 4. I recommend indent or bcpp.
• Project should include a Makefile. 

Scope
The program for this assignment must include at least one example of each of the following:
• User interface (user prompts, curses, commandline options, GUI or something similar). If your program uses a command-line interface, you must use getopt() or getoptlong() to process it.
• Interprocess Communication (signals, pipes, sockets or shared memory) with a second program or thread 
• Database (SQLite3) input and output 

Code Reuse 
An oft heard but seldom seen "best practices" idea is that of code reuse: not re-inventing the wheel, but starting with some base code. The code from previous labs (from text book "Beginning Linux Programming, 4th edition") may be used as a starting point for this assignment.