Biology Forums - Study Force

GOod day,

Hoping your weeks going well!

here is the lab for my CPS 125 lab tomorrow morning. I was wondering if you could let me know if you have any insights on this. I will be attaching the files.

Post Merge: 5 months ago

The TA has given a short extension due to midterms, if its possible to provide your insights, i'd appreciate it!


Thanks!

LAB #5
Purpose:
This lab helps you to apply the concepts of
iteration and, in particular, nested loops in C,
and to provide further practice in
implementing selections in C. In this lab you
are going to determine, from water quality measurements, whether or
not a beach should be closed for swimming. A real world set of
exercises.
Before the lab:
1. Read your notes concerning loops with particular attention to
while and for loops.
2. Read your notes concerning input data from files (FILE, fopen
,fscanf, flose) or file redirection.
During the lab:
PART I: PROGRAMMING EXERCISES
Exercise #1:
The program we will eventually have written in the lab will calculate
the average level of bacteria in the water at various beaches and print
out a message if the beach is safe or should be closed for swimming.
This type of program is often found on midterm tests and/or the final
examination. A similar problem (but not identical) can be found on the
example programs website (see programs 7, 8, and 9). We will do this
program in 11 steps:
A typical data file would look like this:
a. Write a scanf statement to read in one number (int), and another
statement to print out that number.
b. Write a for loop to read in a series of 5 numbers (int), each
iteration reading one number and printing it out.
c. Write one scanf to read in three integers into variables standing
for beach number (int), number of samples (int), number of
organisms per 100 ml of water (int). Choose appropriate names
for the variables like: b_num, num_samples, num_orgs_per_100.
d. Write a scanf line to read in an integer "number of samples" from
the keyboard into the variable num_samples. Following that, write
a for loop to iterate (repeat) num_samples times. In each
iteration have your code read in one value from the keyboard into
a variable (any name will do, here) and print it out. eg: if
num_samples is 8, your code will read a value in the first line of
the body of the for loop and then print it out in the next line,
repeated a total of 8 times. Note that each new read overwrites
the previous value in your variable. REMEMBER: a loop (for or
while, and also if and else for that matter) ALWAYS executes
ONLY a SINGLE statement - which means that you do NOT need
curly braces { } around that one statement. If you want your for
loop to execute two statements (scanf in the value, and then print
it out), they both must be put into a "compound statement" (any
number of statements inside curly braces). This compound
statement acts like a single statement insofar as the for loop is
concerned, so the single compound statement (that is, the two
statements it contains) is executed once each time the for loop
iterates.
e. Now slightly modify the for loop code as follows. Continue to use
the scanf line to read in the number of samples into the variable
num_samples, before the for loop code. However, this time have
each read place each value into the variable named
num_orgs_per_100 ... and then, as before, print out each in the
second line of the compound statement. (Note that each
subsequent read will overwrite the value in num_orgs_per_100
from the previous read, just as happened in the previous section.
We will do something different with those values, below.)
f. This step introduces and arranges data. Your coding is not
changed in this part. In the above, your data has come from the
keyboard. You can continue to do that, but putting the data in a
file (input with redirection or FILE I/O) will certainly cut down on
your work during debugging. Type in your data or create your
data file so that each data line has the following information: two
integers: the beach number and the number of samples; followed
by (on the same line): a series of numbers which are the number
of organisms per 100 ml of water for each sample. These will
eventually go into variables b_num, num_samples, and
repeatedly (as you did, above) into num_orgs_per_100. eg for
beach number 17 with 3 samples: 17 3 2500 3450 1825 You will
eventually write a while loop in your coding (not yet) which will
scanf values into b_num and num_samples. The while loop will be
written to stop when the beach number is -17. The data could
look like this:
18 3 2500 3450 1825
14 2 4800 6000
-17 0
Note that beach # -17 does not exist (hence the 0 samples). That
line is there to signal the end of the file. We will get rid of it later.
g. Write a while loop which uses scanf to read in two values into
b_num and num_samples. You will initially be using a negative
value for the beach number (eg -17) as a sentinel to stop the
iteration. Thus I, II, III, IV, and feof from the lecture notes are
not applicable, at least at this point in the lab. Do not run this
loop yet as it has no way of dealing with the trailing number of
organisms in each data line. If you want to be sure what you have
written works (not a bad idea to save LOTS of headaches later
on), put a single printf in the while loop to output b_num and try
it with a limited data set that does not have the trailing values:
18 3 14 2 -17 2
h. Inside a while loop place your "for loop" to read in the trailing
numbers in each line (num_samples of them). For now these will
be placed (repeatedly) into the single variable
num_orgs_per_100. As before, after each value
(num_orgs_per_100) is read in, print it out so you will be using
the same for loop code as above. Here is how to write the "double
looping". Note that the for loop control variable num_samples is
read in prior to the for loop being executed. You will have to write
a scanf to read the b_num and num_samples BEFORE the while
loop; the while loop condition tests whether b_num is -17 (the
"sentinel" value) or not; if b_num is not -17 the while loop body
executes. In the while loop body, the for loop reads in and
outputs each num_orgs_per_100 value. A copy of the same scanf
as you wrote to precede the loop now reads a new b_num and
num_samples from the NEXT data line. (Note that we have TWO
statements we want to execute inside the while loop - the for and
the scanf ... so they must be in a single compound statement
which will form the while loop body.) After the scanf has input the
first two values on the next line, the while loop test is performed
again ... Note a three things: a) The first scanf statement (before
the while loop) is executed only once. It initializes b_num for the
while loop test, and it also gets num_samples which will be used
to control the for loop doing the input for the remainder of that
first data line. b) The while loop contains only a single statement
- the compound statement { } containing the for loop and the
second scanf statement. c) After the first iteration, the while loop
condition is always testing the b_num value read in by the second
scanf statement. The for loop (inside the while loop) will iterate
(loop) num_samples times, each time reading in one value into
num_orgs_per_100, and then in the second line inside the for
loop printing it out. The while loop will thus read 18 and 3 into
b_num and num_samples, respectively. The first iteration of the
for loop will read and print out 2500; the second time through the
for loop it will read and print out 3450; and the final
("num_samples") time through the for loop it will read and print
out 1825. The while loop will next read 14 and 2 into b_num and
num_samples, respectively. It will then input and print out the
two bacteria count values 4800 and 6000, as you just went
through immediately above. The while loop will continue on to
read the next line of data and in this case the b_num of -17 will
cause the while loop to be finished. You now have a for loop
running successfully inside a while loop.
i. Now, instead of printing out the num_orgs_per_100, they will be
summed. This is done because we want the average of those
values for each line. Remember that the sum variable (pick a
good name like "total" for the summing variable) must be zeroed
before each time you start to add up all the num_orgs_per_100.
Just inside the while loop, zero your total variable right before
entering the summing loop (your for loop). Change the printf
statement in the for loop to a sum statement: total = total +
num_orgs_per_100; After the for loop (still in the compound
statement which is the body of the while loop, but BEFORE you
read in num_samples for the next line - that MUST be the final
statement in the while loop body) write the code to produce the
average number of organisms per 100 ml for the line being
processed. (You divide the sum for that data line by the number
of samples in that line.) Put in a printf in the next line (before the
second scanf) to output that average. Run and test that your
code is producing the correct averages and stopping on the
sentinel value.
j. There is still one job to do with the data for that beach. It must
be determined whether the beach is to be closed or not. Right
after the average has been output, you will need an if statement
to decide whether the beach is to be closed or not. If the average
is below 3500 print out the beach number and a short message
that the beach is safe; if greater than or equal to 3500 print out
the beach number and a short message that the beach is closed.
k. At present, you are using the sentinel value of -17 to stop the
while loop. This is to be changed so that the while loop will stop,
instead, when there are no more data lines in the file (or to be
typed in if you are doing the tedious work of typing in the data
again and again). Use one of the forms I, II, III, IV, or feof from
the notes in Ch 5 to have the while loop stop when the end of
your data file is reached. You will only have to change the scanf
lines and the condition. (Forms II and IV may be the easiest:
remove both your existing scanf's which read the b_num and
num_samples, and they are replaced by a single scanf in the
while condition which reads in b_num and num_samples.) You
can also add several more lines to your data file at this point if
you wish.
Test your program with the following dat files: data5.txt, erie.txt,
huron.txt.
Exercise #2:
a. If your program is fully functional and you still have time to
spare, add a report to count the total number of beaches in the
file and how many are open, and how many are closed.
PART II: DISCOVERY ACTIVITIES
i. Using your text book, or an Internet search (do not ask friends or
TA) or simply by experimenting with Quincy, explain in a few
sentences the difference between these two statements: if (x >
0) and while (x > 0).
PART III: LAB REPORT SUBMISSION
1. Submit the .c file for programming exercise 1 (even if
incomplete).
2. Submit on D2L/Brightspace under Lab #5. Submissions are due
at the end of the lab session. You must submit your work before
leaving the lab.
• During the last half hour you will practice the test environment with
a mock paractical test. The computer will be rebooted into the
proprietary online exam system. Follow your lab TA instructions. You
will see this page section in the exam environment.
• To run a new program, You have 4 steps: 1) Write the code and
save it. 2) Compile the code to check for syntax errors (Compile
button). 3) Build the application (Build button). Run the application
(Run button). Here is an overview of Geany's buttons:
The highlighted options are pretty much all you will need.
i. Open Geany (if not already).
ii. In the program editor, enter the following program:
#include <stdio.h>
#include <math.h>
int
main (void)
{
int number, square;
double sroot;
number = 20;
sroot = sqrt (number);
square = number * number;
printf ("%5d %5.2lf\n", square, sroot);
return (0);
}
iii. Save your program under the name root.c.
iv. Compile, build and run your program (see menu snapshot
above). Make sure that the program displays the correct
numbers 400 and 4.47.
v. Now for question 2:
vi. Write a C program that asks the user for three (3) numbers and
calculates the average. Make sure that your program displays
the answer on the screen (like it was done in program 1).
vii. Save your program under the name average.c.
viii. Compile, build and run your program. Make sure that it displays
correct answer.
ix. That's it! This is the end of the mock practical test. The real test
will work the same way.
After the lab:
1. Review the steps you took to perform the various operations in
the lab.
2. Try to use a do...while loop if you have not already in one of your
programs.
Homework:
• On paper (no computer needed), do the following programming
project (write the code by hand as you would on a test or an
exam).
• Show your homework to your lab assistant at the beginning
of next week's lab.
• If you wish, you may try your solution with the computer to
see if you got the correct solution (no need show the computer
version).
Last modified: January 06 2022 10:23:59.

any luck with this sir?

I just noticed it... Let me take a look, will update...

@@ I did a thorough search, I cannot find something that will help you here :-\

oh wow thats pretty sad, all good tho

Thanks for trying