Design due: in class on Tuesday, March 28th

Code due: Thursday, April 6th by 11:59 PM

Update 3/29: see “Getting Started” section for an update concerning the submitToMarmoset.pl script needed to submit to Marmoset

Update 3/30: corrections to scoring

Update 3/31: due date changed

Getting Started

Start by downloading CS101_Assign03.zip, saving it in the directory CS101 within your home directory.

If you are on Windows, start a Cygwin Bash Shell and run the following commands:

cd h:
cd CS101
unzip CS101_Assign03.zip
cd CS101_Assign03

If you are on Linux, start a terminal and run the following commands:

cd CS101
unzip CS101_Assign03.zip
cd CS101_Assign03

Using Notepad++ (or a Linux text editor such as Pluma), open the file

CS101/CS101_Assign03/OnTarget.cpp

You will add your code to this file.

When you are ready to compile the program, in the Cygwin bash shell (or Linux terminal) window type the command

make

To run the program, type the command

./OnTarget.exe

Important note: The original version of the zip file did not include the submitToMarmoset.pl script needed to allow make submit to work. To fix this problem, run the following command in your CS101_Assign03 directory:

curl -O http://faculty.ycp.edu/~dhovemey/submitToMarmoset.pl

Your tasks

Design

Your design artifact should contain control flow sketches for:

generating the scores and storing them in an array
computing a histogram of the scores

Program

Your task is to write a program that simulates an archer firing arrows at a target.

The target is a circle whose diameter is 1,900 units. The center of the target as at the point (0,0). When an arrow hits the target, its score is calculated based on how far it was from the center of the target:

If it was within 50 units of the center, it is a bullseye, and earns 1,000 points
If it was between 50 and 150 units from the center, it earns 900 points
If it was between 150 and 250 units from the center, it earns 800 points
etc.

Any arrow more than 950 units from the center misses the target entirely, and earns 0 points.

To simulate firing an arrow, the program should compute random x and y coordinates in the following way. Compute the sum of 8 random integers whose values are between 0 and 275, inclusive. Then subtract 1,100 from the sum. When calculated in this manner, both x and y coordinates will be in the range ±[0..1,100].

You can calculate the distance from an arrow’s location and the center of the target by computing the square root of the sum of the squares of the arrow’s x and y coordinates.

As a score is computed for each simulated arrow, the program should do two things:

It should update a histogram array in which the elements store the counts of arrows earning 1,000 points, 900 points, 800 points, etc.
It should add the score to an overall scores array, so that when all of the simulated arrows have been fired, the array records all of the individual scores

The program should simulate firing exactly 1,000 arrows.

The output of the program should consist of two parts.

The first part is a “graphical” histogram presenting a visual representation of the number of arrows earning each of the 11 possible scores. Each character in the bar should represent 5 arrows. The integer count for each score should be printed. (Try to match the output shown in the examples as closely as possible.)

The second part is computed statistics about the scores, specifically the mean, median, and standard deviation of the scores.

Example run:

1000: [  36] =======
 900: [ 165] =================================
 800: [ 228] =============================================
 700: [ 223] ============================================
 600: [ 184] ====================================
 500: [ 110] ======================
 400: [  36] =======
 300: [  16] ===
 200: [   2] 
 100: [   0] 
   0: [   0] 
Median score is 700.00
Mean score is 708.00
Standard deviation is 156.83

Another example run:

1000: [  25] =====
 900: [ 167] =================================
 800: [ 278] =======================================================
 700: [ 242] ================================================
 600: [ 157] ===============================
 500: [  94] ==================
 400: [  28] =====
 300: [   6] =
 200: [   3] 
 100: [   0] 
   0: [   0] 
Median score is 700.00
Mean score is 721.90
Standard deviation is 144.19

Hints

When printing the histogram, use field widths to ensure that the figures and the bars align correctly.

To compute the median, it will be helpful to arrange the scores in sorted order (from least to greatest). You can do this by calling the qsort function as follows:

qsort(scores, 1000, sizeof(int), compare);

This assumes that your array of scores is called scores, that the array has int elements, and that there are exactly 1,000 elements. The compare function (included in the skeleton file) is used to compare scores.

See the following web page for information about computing standard deviation:

http://www.mathsisfun.com/data/standard-deviation.html

Grading

Your grade (out of 100 points) is determined as follows:

Design artifact: 10 points
Simulating arrows being fired at the target: 10 points
Scoring each arrow: 10 points
Storing scores in an array: 15 points
Computing histogram of scores: 15 points
Printing histogram of scores
- Count for each bucket: 10 points
- Bar for each bucket: 5 points
Computing median: 5 points
Computing mean: 5 points
Computing standard deviation: 5 points
Good coding style: 10 points

To earn full credit for coding style, make sure your program uses correct indentation, uses meaningful variable names, and has comments explaining the purpose of each section of code.

Submitting

Your design will be checked off in class on the day the designs are due.

To submit your program, make sure your OnTarget.cpp file is saved, and in the Cygwin window type the command

make submit

Enter your Marmoset username and password (which you should have received by email.) Note that your password will not be echoed to the screen. Make sure that after you enter your username and password, you see a message indicating that the submission was successful.

If the make submit command does not work, you can submit using the web interface (see the link for details).

Important: Make sure that you check the file(s) you submitted to ensure that they are correct. Log into the server using the following URL (also linked off the course homepage):

https://cs.ycp.edu/marmoset/

You should see a list of labs and assignments. In the row for assign03, click the link labeled view. You will see a list of your submissions. Download the most recent one (which should be listed first). Verify that it contains the correct files.

You are responsible for making sure that your submission contains the correct file(s).