EECS281 Project 0- Statistics Solution

Project Identifier
EECS 281 Project 0: Statistics
Project Identifier: 39E995D00DDE0519FDF5506EED902869AEC1C39E
You MUST include the project identifier at the top of every file you submit to the autograder as a comment. This includes all source files, header files, and your Makefile (search for the TODO in the Makefile, and remember that it uses # for comments not //):
// Project Identifier: 39E995D00DDE0519FDF5506EED902869AEC1C39E

Overview
The goal of this project is to help you become more familiar with command line processing, as well as how a vector works and the vector member functions .resize() and .reserve(). Reading the Lab01-Prelab document will help with Project 0.
Not only will this help you with command-line processing that is much more complicated than you did in EECS
280, it will also familiarize you with the EECS 281 Autograder.
There are 5 videos to help you get started on our EECS 281 YouTube Channel; pick one of the first three, then watch both of the last two:
● Using a Mac and Xcode
● Using Windows, Visual Studio and the WSL
● Using Windows and VSCode w/ WSL
● Project 0 tutorial
● Using our Makefile
This also means there's one starter file for everyone: Project0-starter.tar.gz
Command Line
The getopt_long() function has several parameters, but the two most important are an array of structures and a double-quoted string. In the Lab01-Prelab document, the array is declared like this:
static struct option longopts[] = {
{ "add", no_argument, nullptr, 'a' },
{ "delete", required_argument, nullptr, 'd' },
{ nullptr, 0, nullptr, '' } };
This says that there are two valid command line options, "add" and "delete", and that they have short forms 'a' and 'd', respectively. The third line is like a '' for the array of options: it allows getopt_long() to know when it’s reached the end. The second field on each line indicates whether that option is followed by something else that is not an option. The no_argument means that option is not followed by anything else, while required_argument means it must be. For example, these would be valid command lines for the prelab sample program:
./lab1-sample --delete something
./lab1-sample -a
./lab1-sample --add -d test
Notice that delete/d is always followed by another “thing” (thus that thing is required), whereas add/a is never followed by another “thing” (except possibly the start of a new option).
The second part is the double-quoted string. It’s redundant to have both the array of structures and the double-quoted string, but we’re stuck with it. The sample program string is "ad:". The single-letter options from the array are repeated, and any required_argument has a colon following it.
Vector Size
Think of a vector as having two sizes: how many items are stored in it right now (referred to as the size), and the capacity before it has to resize (this is the size of the dynamic memory that it allocated via new). If you create a vector and just use .push_back(), items are added, the size increases linearly, but the capacity doubles any time there is not enough room (some implementations might multiply the size by a different factor, but it’s always multiplicative). So if you keep using .push_back(), an empty vector would grow from 0/0 (size/capacity) to 1/1, 2/2, 3/4 (notice that one space is wasted), 4/4, and then 5/8 (the capacity doubles from 4 to 8, then there’s room to add the latest item). Whenever the vector grows by doubling, here’s what has to happen:
1) A new block of dynamic memory is allocated, of the new capacity
2) The existing elements are copied from the old block to the new block
3) The old block of dynamic memory is deleted
4) The internal pointer is changed to point to the new block of dynamic memory 5) The.push_back() can finish
Step (2) takes time, and you can end up with wasted memory. Consider 1025 elements: the size doubles 1, 2, 4, …, 512, 1024, 2048. But now only 1025 elements are used out of 2048 allocated, which is almost 50% wasted memory. If you know ahead of time how much data you will need room for, you can use the .resize() or .reserve() member functions to change the size of the vector before reading. You will know that the size is exactly right, with no wasted memory.
The .resize() member function changes both the current size and the capacity. Once this is done, you can use [] to access any valid index in the range [0, size). If you use .resize() and then immediately use .push_back(), you will end up with extra elements. For example, if I .resize() a vector of integers to 10, it has 10 copies of the value 0. If I then .push_back() the value 25, I have 10 copies of 0 followed by the value 25.
The .reserve() member function changes only the capacity, leaving the current size unchanged. Thus to add more elements you would need to use .push_back(). If you use .reserve(10) and then immediately try to access the data at index 0 (using square brackets), it’s an invalid access.
Finishing Project 0
You should first complete the getMode() function; until that is done none of the other functions can be called. After that’s done, pick one of the three functions that read data and complete it. You can use the two input files provided to test that your program is working. The file sample-n.txt is intended to be used with --mode nosize, while the file sample-r.txt will work with the resize or reserve modes. When your program is working, the correct answers are an average of 13.39, and a median of 12.70 (both files and any valid command line flag should give the same results).
Autograder (9 points total over 9 test cases)
Before submitting to the autograder, be sure that:
● The executable should be named project0 (look in the TODO section of the Makefile)
● Every source code and header file contains the following project identifier in a comment at the top of the file: // Project Identifier: 39E995D00DDE0519FDF5506EED902869AEC1C39E ● The Makefile must also have this identifier (already done for you for Project 0).
● DO NOT copy the above identifier from the PDF! It might contain hidden characters. For Project 0, the identifier is already included in the provided project0.cpp file. Future projects will have it in a text file for you to copy to your code.
After you have your program working, typing the command “make fullsubmit” (again without quotes) will produce a tarball name fullsubmit.tar.gz, which you can then upload to the autograder for further testing and scoring. There are 9 tests on the autograder, each test has a two letter name: S|M|L (Small, Medium, or
Large input file), followed by N|V|Z (Nosize, reserVe, or resiZe).
Late Days