CSCI 330 Assignment 3 SOLUTION

CSCI 330 Assignment 3 

Implement cat command (50pts)
Purpose
The purpose of this assignment is to provide practice using the system calls for working with files on a UNIX
system. You will be writing a basic implementation of the cat command using C++.
Description
As you should recall, the cat command takes a list of files as command line arguments. It then opens each
file in turn, writing each file’s entire contents to standard output in the order they were supplied.
You will be responsible for writing a C++ program that implements this behavior. If you are unclear on what
your output should look like, compare your program’s output to the output from the actual cat program. As
seen in its manpage (man cat), the actual command does have some additional options that can be used, but
other than the single dash, “-”, for standard input, you don’t need to implement those.
Requirements
1 The user can pass as many filenames as they wish as command line arguments. Your program must be
able to handle all of the files, no matter how many are passed.
2 No matter how long each file is, your program must be able to read and output all of the data it contains.
This may be tested with a file that is larger than all of the RAM available to you, so you need to find a
way to print its contents anyway.
3 All of the data must be displayed, even if the files contents have non-text data. Notice that this means
cout << will not be sufficient on its own.
4 The UNIX system calls that we spoke about in class must be used to implement the reading portion.
They may be used for the writing portion as well, but this is not required for this assignment. This
means that the C++ file stream classes are not permitted to be used for the file input. (Use open, read,
close.)
5 If “-” (a single dash) on its own is specified as one of the files to read and output, read the data from
standard input instead of opening a file. Do not open a file called “-”.
6 Make sure to clean up after you are done with each file that you have opened, calling close on its file
descriptor. Remember that no file was opened in the case of “-” from above.
7 Make sure to properly document your code. This includes a documentation box at the top of your
program and before each function you write. You must also include comments on the portions of the
code that do important work in order to explain what is going on, and why. If documentation is missing.
Your grade on the assignment will suffer.
8 Your code should compile properly with just g++ and no special flags on turing and/or hopper.
What to turn in?
All you need to turn in for this assignment is the C++ source code file. Submit it via Blackboard. It is allowed
to have any of the file extensions appropriate to a C++ source code file (.C, .cc, .cpp, etc.), but I recommend
“.cc”.