COMP 2103X1 Assignment 2 Due Thursday, January 26 by 7:00 PM General information about assignments (important!): http://cs.acadiau.ca/~jdiamond/comp2103/assignments/General-info.html Information on passing in assignments: http://cs.acadiau.ca/~jdiamond/comp2103/assignments/Pass-in-info.html Information on coding style: http://cs.acadiau.ca/~jdiamond/comp2103/assignments/C-coding-style-notes [1] A filter program is a program which reads its input from “standard input” (“stdin”) and writes its output to “standard output” (“stdout”). Filter programs are useful because they make it easy to combine the functions they provide to solve more complex problems using the standard shell facilities. Filter programs are also nice to write, because the programmer doesn’t have to worry about writing code to open and close files, nor does the programmer have to worry about dealing with related error conditions. In some respects, filter programs are truly “win-win”. Write a filter program which uses getchar() to read in characters from stdin, continuing until end of file (read the man page and/or textbook to see the details on getchar(), or, heaven forbid, review the class slides). Your program must count the number of occurrences of each character in the input. After having read all of the input, it outputs a table similar to the one below which, for each character seen at least once, lists the total number of times that character was seen as well as its relative frequency (expressed as a percentage). Note that the characters \n, \r, \t, \0, \a, \b, \f, and \v (see man ascii) must be displayed with the appropriate “escape sequence”. Ordinary printable characters must be output as themselves. Non-printable characters (see man isprint) must be printed with their three-digit octal code (see man printf). You can get input into a filter program (a2p1 in this case) in three ways: (a) “pipe” data from another program into it, like $ echo blah blah | a2p1 (b) “redirect” the contents of a file into the program, like $ a2p1 < some-file (c) type at the keyboard, and (eventually) type ^D (control-d) at the beginning of a line to signify end of file. Your output must look like the following, for this sample case: $ echo ^Aboo | a2p1 Char Count Frequency -------------------------- 001 1 20.00% \n 1 20.00% b 1 20.00% o 2 40.00% Note: in the above examples, and from now on in this course’s assignments, text in red is text that the human types, and a “$" at the beginning of a line like that represents the shell prompt. 1 http://cs.acadiau.ca/~jdiamond/comp2103/assignments/General-info.html http://cs.acadiau.ca/~jdiamond/comp2103/assignments/Pass-in-info.html http://cs.acadiau.ca/~jdiamond/comp2103/assignments/C-coding-style-notes Note that I entered a ^A (control-a, not the circumflex character followed by the capital A) by typing ^V^A. The ^V tells your shell that you want it to interpret the next character literally, rather than to use any special meani.

1. COMP 2103X1 Assignment 2
Due Thursday, January 26 by 7:00 PM
General information about assignments (important!):
http://cs.acadiau.ca/~jdiamond/comp2103/assignments/General-
info.html
Information on passing in assignments:
http://cs.acadiau.ca/~jdiamond/comp2103/assignments/Pass-in-
info.html
Information on coding style:
http://cs.acadiau.ca/~jdiamond/comp2103/assignments/C-
coding-style-notes
[1] A filter program is a program which reads its input from
“standard input” (“stdin”) and writes
its output to “standard output” (“stdout”). Filter programs are
useful because they make it easy
to combine the functions they provide to solve more complex
problems using the standard shell
facilities. Filter programs are also nice to write, because the
programmer doesn’t have to worry
about writing code to open and close files, nor does the
programmer have to worry about dealing
with related error conditions. In some respects, filter programs
are truly “win-win”.
Write a filter program which uses getchar() to read in characters
from stdin, continuing until
end of file (read the man page and/or textbook to see the details
on getchar(), or, heaven forbid,

2. review the class slides). Your program must count the number
of occurrences of each character in
the input. After having read all of the input, it outputs a table
similar to the one below which, for
each character seen at least once, lists the total number of times
that character was seen as well as
its relative frequency (expressed as a percentage). Note that the
characters n, r, t, 0, a, b,
f, and v (see man ascii) must be displayed with the appropriate
“escape sequence”. Ordinary
printable characters must be output as themselves. Non-
printable characters (see man isprint)
must be printed with their three-digit octal code (see man
printf).
You can get input into a filter program (a2p1 in this case) in
three ways:
(a) “pipe” data from another program into it, like
$ echo blah blah | a2p1
(b) “redirect” the contents of a file into the program, like
$ a2p1 < some-file
(c) type at the keyboard, and (eventually) type ^D (control-d) at
the beginning of a line to
signify end of file.
Your output must look like the following, for this sample case:
$ echo ^Aboo | a2p1
Char Count Frequency
--------------------------
001 1 20.00%

3. n 1 20.00%
b 1 20.00%
o 2 40.00%
Note: in the above examples, and from now on in this course’s
assignments, text in red is text that
the human types, and a “$" at the beginning of a line like that
represents the shell prompt.
1
http://cs.acadiau.ca/~jdiamond/comp2103/assignments/General-
info.html
http://cs.acadiau.ca/~jdiamond/comp2103/assignments/Pass-in-
info.html
http://cs.acadiau.ca/~jdiamond/comp2103/assignments/C-
coding-style-notes
Note that I entered a ^A (control-a, not the circumflex character
followed by the capital A) by
typing ^V^A. The ^V tells your shell that you want it to
interpret the next character literally, rather
than to use any special meaning (during command line entry)
that the next character might normally
have. (Question: what does your shell do, when typing in a
command line, if you type ^A without
first entering ^V? Try it and see if you can figure it out. You
might find it useful to know this, and
to know what ^E and ^W do as well.)
You should run your program on a few different inputs to
demonstrate to the marker that you have

4. thought about (and programmed for!) the different cases that
could occur. If you redirect input
from a data file, rather than using “cat” to display the contents
of your file when creating your
transcript file, use a command like $ od -bc test-data-1 .
[2] The printf() function in C is very powerful and convenient,
but it takes some getting used to.
This question will give you experience with this function.
When you are testing functions like printf() which produce
formatted output, sometimes you
want to make sure that the spaces in the output are the ones you
expect. To make it obvious where
all the white space came from, it is often convenient to enclose
a format specification inside a pair
of characters that are not otherwise used in that output. For
example, if you use something like
printf("|%f|n", x)
then you will know whether the %f format specification
produced any spaces before the newline.
The constant M_PI, an approximation to the value of � , is
defined in the system include file math.h.
Write a program which prints out the value of M_PI using each
of the following specifications, one
specification per line of output:
(a) fixed point notation, field width of 9, 5 digits of precision,
left justified
(b) fixed point notation, field width of 9, 5 digits of precision,
right justified
(c) fixed point notation, field width of 9, no precision
specification, right justified
(d) fixed point notation, field width unspecified, 5 digits of

5. precision, right justified
(e) scientific notation, field width 9, 5 digits of precision, right
justified
(f) scientific notation, field width 9, 5 digits of precision, left
justified
(g) scientific notation, field width 14, 5 digits of precision,
right justified
(h) scientific notation, field width 14, 5 digits of precision, left
justified
As an example of what your output might look like, here is one
sample line of output:
|3.14159 | is field 9, precision 5, left justified
Examine your output and try to understand what the printf()
function is doing, especially any
outputs that you find surprising.
2
[3] These days, many people are very concerned with the
protection of private information. This
program will do a very rudimentary form of encryption. (Don’t
use this for anything you want to
keep secret!)
Write a filter program to encrypt standard input as follows:
(i) upper case letters between ‘A’ and ‘M’ are replaced with the
lower case letter 13 positions
further along in the alphabet (e.g., ‘B’ is replaced with ‘o’);
(ii) upper case letters between ‘N’ and ‘Z’ are replaced with the
lower case letter 13 positions

6. earlier in the alphabet (e.g., ‘Z’ is replaced with ‘m’);
(iii) lower case letters between ‘a’ and ‘m’ are replaced with the
upper case letter 13 positions
further along in the alphabet (e.g., ‘d’ is replaced with ‘Q’);
(iv) lower case letters between ‘n’ and ‘z’ are replaced with the
upper case letter 13 positions
earlier in the alphabet (e.g., ‘y’ is replaced with ‘L’);
(v) the four punctuation characters ‘.’, ‘,’, ‘!’ and ‘?’ are
replaced with, respectively, ‘!’, ‘?’, ‘.’
and ‘,’.
Of course, an encryption program is no use without a
corresponding decryption program. A bit of
thought (or experimentation) should show that this program will
decrypt its own output.
To test your program, create a few text files; some small, some
big. Then run some tests which will
convince the marker of the following things:
(i) the output of the program looks different than the input; and
(ii) running the output of the program through the program a
second time recovers the original
data.
You can make use of the Unix utilities diff and/or cmp, as well
as cat, to help convince the
marker that your program works. Here is a sample run with a
small number of tests. Note that you
don’t need to cat big files into the script file, but you can use ls
-l or wc to show the marker
that the files were big.
$ <cat a2p3.c, show gcc step, ...>

7. $
$ cat test1.dat
This is a short file.
Is it long enough, or should it be longer?
$
$ a3p1 < test1.dat
gUVF VF N FUBEG SVYR!
vF VG YBAT RABHTU? BE FUBHYQ VG OR YBATRE,
$
$ a3p1 < test1.dat | a3p1
This is a short file.
Is it long enough, or should it be longer?
$
$ wc test2.dat
1241 3394 44616 test2.dat
$ a3p1 < test2.dat > test2.dat.crypt
3

8. $
$ wc test2.dat.crypt
1241 3394 44616 test2.dat.crypt
$
$ cmp test2.dat test2.dat.crypt
test2.dat test2.dat.crypt differ: byte 3, line 1
$
$ a3p1 < test2.dat.crypt > test2.dat.crypt.decrypt
$
$ cmp test2.dat test2.dat.crypt.decrypt
$
Notice that, as is common for Unix programs, cmp says nothing
in the “success” case, which for
cmp is when the two files are identical.
The third (red) command entered above is interesting. It shows
how the Unix shell (command
interpreter) allows you to send the output of one program (the
first a2p3) into the input to another
program (in this case the second a2p3). This is an extremely
powerful feature of the shell,
especially since your program does not have to do anything
special to make this happen; as far as
your program is concerned, it is reading from standard input and

9. writing to standard output. The
fact that those may be the keyboard, screen, a file or another
program generally don’t matter to
your program. (In fact, the occasional program does care, but
that is an uncommon circumstance.)
In the partial script above I showed a test with a short file, and
a long file. I showed that (some)
letters got encrypted as they should, and that punctuation is
properly encrypted. I also showed that
my program works with a fairly long file, but you might want to
try a bigger file yet. And you
might consider using the head program to output just the first
few lines of a very long file to your
script file.
Should anything else be tested? Are there any boundary cases
here?
Did you use functions in any of these questions? Should you
have? Did you document them
correctly?
Does you program “blow up” on unexpected input, or does it
deal with bad input in a “graceful”
way?
How does your program deal with boundary conditions, if there
are any?
Did you remember to put all required comments in? Does your
program call out for any other
comments in the body of the code?
4

10. Fire Prevention Unit II Project
Community ISO Rating
For this assignment, you will research your community, and
calculate a rating similar to ISO/PPC though NOT using an
ISO/PPC rating scale. For this project, you will be using our
own rating scale, which is found in the grid below.
Emergency Communications
System
Fire Department
Structure
Water Supply
System
Community Efforts Risk
Reduction
0
No emergency call center
Non staffed
No public water
supply
No programs or
enforcement
1
Uses direct dial 7 or 10 digit
number to reach either police or
Staffed by first
responders only for
No public water
supply; only “dry wells” or ponds,
Annual fire prevention
activities limited to schools only

11. fire ; i.e. 222-1212 or 222-2323 or
901-222-1212 or 901-222-2323
EMS calls; stations are not open 24/7
lakes, and streams for drafting
2
County 911 system non Enhanced
system; separate police & fire dispatching
Staffed by part-time
paid-per-call EMS personnel only; one station open 24/7
Municipal fresh water
treatment; no hydrants
Annual fire prevention
activities limited to schools and senior centers
3
County E-911 (Enhanced) system
with central police & fire dispatching
Staffed by full-time
paid EMS personnel only; only one station open 24/7
Municipal fresh water
treatment; hydrants spaced greater than
1,000 feet apart
Annual fire prevention
activities and daily fire inspections of high risk occupancies
4
Municipal 911 system; non
Enhanced system; separate police
& fire dispatching
Staffed by full-time
paid EMS and fire suppression personnel; limited number of
stations
24/7
Municipal fresh water
treatment; fire hydrants spaced greater than 500 feet apart
Annual fire prevention and
public fire safety programs for all audiences

12. 5
Municipal E-911 (Enhance)
system with central call intake center with central dispatch or
police and fire dispatch on own after E-911 call is received
Staffed by full-time paid EMS and fire
suppression personnel; stations
positioned
Municipal fresh water treatment; fire
hydrants spaced 500 or less apart; total
community coverage
Staffed full-time Fire
Prevention Division; annual fire prevention activities; fire
inspections; fire investigations & code enforcements
For this project, you will conduct an ISO/PPC “like” analysis of
your community. Using a five-point rating scale where 0 is the
worst and 5 is the best, analyze and rate your community’s
ability to address the four components used by ISO/PPC in its
rating system. Keep in mind that this rating is similar to, but not
the same as, the ISO/PPC rating scale.
Primary differences include: this scale is backwards in that 0 =
worst and 5 = best, and greater details are not included in each
of the four categories.
Using the rating-scale grid from above, analyze your own
community’s fire service capabilities. If you are a fire service
employee, you will most likely know how your community
operates and what services (emergency communications, fire
department structure, water supply, and risk reduction) are in
place.
If you are non-fire service employee, you will most likely be
able to assess two categories, emergency communications and
water supply, by simply knowing your emergency call system
and seeing fire hydrants on the streets. For the two remaining
categories, you will need to call your local fire department and
speak to a firefighter, or fire officer, who should be pleased to
answer your questions. You could also, time permitting, take a

13. trip to the fire department and ask for a tour for answers to your
questions.
To finish the project, you will need to construct a grid similar
to the one above, or identify each of the four categories with
their corresponding numerical rating number. Once you have
analyzed your community and composed your numbering
system, write a brief paragraph for each of the four categories
that supports your number selection for each category.
There is no “right” or “wrong” response here, as every student
may have a differently constructed community. Your final paper
should be written in proper APA format, and include citations
for sources as needed.
You must have a title page, double-spaced, with only the
following information written in the center: title of paper, your
name, and university name. No reference page is required, no
abstract is required, and no headers are required.
The finished paper should be a minimum of three pages of
written grid/graph and narration; however, not more than four
pages in length. This page requirement does not include your
cover page.
***Please no Plagiarism***