Description
For this assignment, we will be building a server we can netcat into to play a simple word guessing game.
Server Details
The server should support up to 5 clients, and cannot not use fork() or threads. Since you will potentially
have multiple clients, you will need to make use of the select() call.
The program will take four arguments: ./word_guess.out [seed] [port] [dictionary_file]
[longest_word_length]
It should use TCP and listen on the port given as the second arguemnt [port].
When the server starts, and whenever a game finishes, it should select a word randomly from a dictionary,
which will be referred to as the secret word. The filename of the dictionary, which just has one word per
line, is passed in as the third argument to the program ([dictionary_file]), and the length of the longest
word (number of letters) is passed in as the fourth argument ([longest_word_length]). Word lengths will
not exceed 1024 bytes, and will not exceed [longest_word_length]. An example dictionary can be found
here. The example dictionary does use ISO-8859-1 encoding instead of UTF-8, so don’t be surprised if you
see strange characters in your terminal when using this dictionary. The autograder input will only use A-Z
and a-z, you do not need to write code in your solution to handle any character encoding issues. Usernames,
guess words, and secret words are not case sensitive, “Bob”, “bOB”, and “bob” should all be treated as the
same thing.
To make the grading deterministic, you should read in the entire dictionary once, sort the dictionary (C
users may want to look at qsort(), C++ users may want to look at std::sort()), and then immediately
after sorting, use srand() with the [seed] provided as the first argument to the program. Secret words
should then be selected by using rand() % dictionary_size.
Usernames
When a client joins, the server should send a message asking the client to select a username, which will be
used to uniquely identify the player among all currently connected players: Welcome to Guess the Word,
please enter your username.
If a client disconnects, its username is no longer reserved. For example client 1 could be the first to connect
and claim the username bob: Let’s start playing, bob
If client 2 then connected and requested bob, the server would reject the username by asking for the username
a second time: Username bob is already taken, please enter a different username
If client 1 then disconnected and client 3 connected and claimed the username bob, the game would continue
with client 3 being bob. Let’s start playing, bob
(continued on next page)
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Gameplay
(Updated 10/6) Once a username is selected, the server should then notify that user about how many
players are currently playing (including the new user), and what the length of the secret word is: There
are 3 player(s) playing. The secret word is 5 letter(s).
Any user can send as many guesses as they want, there is not a concept of “taking turns” in this game.
However, each message should contain one word of the same length as the secret word, followed by a
newline. Whenever the server receives a word from a user (called a guess word), it should send a message
to all connected users in the format: Z guessed G: X letter(s) were correct and Y letter(s) were
correctly placed.
X counts duplicate letters as a separate letters, so if the secret word is GUESS and bob sent a guess word of
SNIPE, the message would be:
bob guessed SNIPE: 2 letter(s) were correct and 0 letter(s) were correctly placed.
(Once for one S and once for the E.)
Similarly, if the sceret word is GUESS and the guess word is CROSS, the response would be:
bob guessed CROSS: 2 letter(s) were correct and 2 letter(s) were correctly placed.
(Once for each S in the secret word.)
Finally, if the secret word is GRUEL and bob guesses spill, the response would be:
bob guessed spill: 1 letter(s) were correct and 1 letter(s) were correctly placed.
(Only one L counts since there is only one L in the secret word.) Note that game is not case-sensitive.
(Updated 10/6) If a user correctly guesses the secret word, all connected users should receive the message
Z has correctly guessed the word S, and then all users should be disconnected from the server. The
server should continue to run and should select a new word. Z is the username of the user who correctly
guessed the word, and S is the secret word. If a user sends a guess word that is not the correct length, the
server should send an error message to only the user with the invalid guess, but should not disconnect that
client: Invalid guess length. The secret word is 5 letter(s).
Submission
You should handle a client quitting at any point during the game, as well as any other error cases you think
of. You can provide any decisions or other comments for the graders to read in a README.txt file. Like
Assignment 1, you should submit a Makefile that produces word_guess.out and use C or C++. Also like
the previous assignment, we will provide libunp.a, unp.h, and config.h in the same directory as your files are
built, and to ensure compilation if using these features you should have libunp.a in your compile line and
should use clang instead of gcc.
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