CS 159 – Lab #7

CS 159 – Lab #7
What will you submit? A single C-file will be submitted electronically via the guru server. An example submission was
conducted as part of the Account Configuration Activity. If you have a concern regarding how to submit work, please
contact course staff prior to the deadline for this, and all, assignments. The programming assignment is due on Friday
March 26, 2021 at 11:00pm (LOCAL WEST LAFAYETTE, IN TIME). No late work will be accepted.
Weekly Quiz #7:
The weekly quiz will be available (Week 10 module on Brightspace) until the same date and time that the programming
assignment is due. It is strongly recommended that you complete the attached problems, the programming assignment,
and watch all relevant lectures before attempting the quiz.
The quiz will emphasize chapter 5 and 6 material, the written problems in this document, the lab programming
assignment, and the course programming and documentation standards as used in this lab. Quiz questions are presented
one at a time and cannot be revisited. Be sure to save your answers to each question and to finish your quiz to ensure it
is submitted for grading. Most problems on lab quizzes will be multiple-choice or true-false. Each quiz has a 15-minute
time limit.
Collaborative Teaming:
• How do I know who is on my lab team?
◦ On-campus students: TAs have contacted their students via e-mail.
◦ On-line students: Visit the Start Here module on Brightspace and locate the Distance Learning Team
Assignment spreadsheet.
• What if a partner does not respond to your communication? Then the remaining active partners need to be
prepared to proceed on the assignment to meet the deadline.
• Groups are expected to communicate to share their ideas when it comes to solving the conceptual and
programming problems associated with this lab. You may find a collaborative document to be a helpful way
to share thoughts on the written problems and to formulate the logic for the programming problem. Other on-line
tools may come in handy when trying to collaborate on specific segments of code, just make sure they protect
your code from being posted publicly! One popular service from previous semesters is codeshare.io.
• As a group you must determine who will make the final submission for your group, when that submission
will be made, and how the concerns regarding submission will be communicated with the other members. Only
one person per group will make submissions for the entire group. The grader for your section cannot be
expected to grade submissions from multiple members of the same group to determine which submission you
actually want graded.
◦ In order for each member of the group to get credit for the programming problem associated with this lab,
their Purdue University e-mail address must appear in the assignment header.
• How might collaboration be useful on this particular programming assignment?
◦ The logic and length of this programming assignment are not nearly what you've been experiencing on recent
and current homework assignments. There are a lot of little, but very important, programming concepts and
course standards within this problem. We will build upon these concepts, not necessarily the numbering
systems problem, for the remainder of the term. Take the time to collaborate with your lab partners on the
written problems and reviewing the idea of numbering systems before you begin to write any code.
◦ Did your first midterm score not meet your expectations? Share that with your lab partners and insist on a
collaborative experience that will help all learn the course material and ensure a complete effort for lab #7.
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(Task #1) - Solve the following problems related to material found in Chapter 5, Chapter 6, and the course
standards.
Statement True or False
The use of arrays, including character pointers to represent string data would violate requirements of this
assignment and result in no credit being awarded for your effort. TRUE
Section 5.3
Multiway selection chooses among several alternatives.
When different variables are being evaluated as expressions it is better to use a nested if...else
rather than the multiway else-if.
The switch construct can only be used when the selection condition reduces to an integral expression.
The control expression that follows the keyword switch may be a character expression.
When the selection is based on a range of values, or the condition is not integral, we use the else-if
for our multiway selection needs.
The case label represents an integral type value that is a possible result of the control expression.
Each switch case label is the keyword case followed by a constant expression inside of single quotes.
Associated with a case label is zero or more executable statements.
When the statements associated with one case have been executed the program flow continues with the
statements for the next case.
The course standards limit the use of the break statement to only switch statements.
No two switch case labels can represent the same constant expression value.
It is always a logical error to associate two switch case labels with a common set of actions.
The maximum number of actions that can be associated with a switch case label is one.
The break statement results in the control of the program exiting the switch statement.
In an else-if the if condition is evaluated first and additional else-if conditions are evaluated
until a condition is found to be true.
Only the statements associated with the first true condition are executed in a multiway else-if
construct.
The else is executed only when all previously evaluated conditions are false.
The else does not have a condition associated with it.
Section 5.6
Negative logic refers to any expression that begins with a NOT operator or that contains multiple NOT
operators within.
Complementing a condition is one way to potentially remove negative logic from an expression.
The only way to complement a NOT operator is with another NOT operator.
When writing a selection construct the most probable conditions should come before those that occur
less frequently.
It is possible to indicate on a structure chart when a user-defined is called from within a section
construct.
Solve the following problems on pages 290-293 of your C programming text: 30, 31, and 32.
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Solve the following problems related to material found in Chapter 5, Chapter 6, and the course standards.
Statement T/F
The contents of a loop have been identified to be repeated in a program.
An iteration is one execution of all statements found inside the body of a loop.
The initialization of the loop control variable must take place outside the body of a pretest loop.
The condition that determines whether the task to repeat is finished is known as the loop control expression.
In a pretest loop the control expression is evaluated before each iteration, including the first iteration.
In a post-test loop the minimum number of times that the statements found inside of the loop are executed is
one.
The action that is responsible for changing the result of the loop control expression from true to false is the
loop update.
The loop control variable is commonly a part of the loop control expression and the recipient of the loop
update action.
In an event-controlled loop we know the number of times that the actions found inside the body of the loop will
be executed.
A counter-controlled loop may execute a constant number of iterations.
It is possible for the number of times a counter-controlled loop will iterate to depend on the value of a single
variable or expression.
The number of times that the loop control expression is evaluated is one more than the number of iterations in a
pretest loop.
The while loop requires the use of parentheses around the loop control expression.
The do-while loop will terminate with a semicolon after its loop control expression.
Course standards prohibit the use of break to terminate any repetition construct.
Similar to their required use in the if construct it is a course standard to always make use of { and } with all
looping constructs.
A limited amount of control structures are permissible in the main function to ensure that it is the main
function which makes most of the function calls for a program.
A nested loop is a repetitive process contained inside of another repetitive process.
One approach to potentially make solving problems that require nested loops easier is to separate each
repetitive process into its own function.
In order for two, or more, repetitive processes to be considered nested they must appear in the same userdefined function.
Input validation is an example of an event-controlled problem.
Selection by itself is insufficient for input validation because it provides only a finite number of opportunities
for the user to input valid data.
In this course you will be expected to validate for the input of both the range of acceptable values and the
correct data type.
It is expected for many cases that the code for the validation of input be found in the same function that
contains the prompt for input and scanf statement.
The short-circuit method of evaluating logical expressions does not apply to loop control expressions.
Control-forcing statements such as break, continue, exit, and the use of multiple return statements in a
user-defined function are prohibited by course standards as mechanisms to terminate repetitive processes.
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Complete the following table from page 309 of the C programming text (Table 6-1):
Pretest Loop Post-test Loop
# of times loop control expression is
evaluated
# of times loop control expression is
evaluated
# of times actions inside the body of the loop
are executed
# of times actions inside the body of the
loop are executed
Minimum # of times loop is iterated Minimum # of times loop is iterated
Use the table below to trace the execution of the loop provided:
 int x = 3415263;
 int ct = 0;
 while(x > 0)
 {
 if(x % 2 == 0)
 {
 ct++;
 }
 x = x / 10;
 }
End of Iteration # Value of X Value of CT
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Use the table below to trace the execution of the loop provided:
 int x = 3415263;
 int ct = 0;
 do
 {
 x = x / 10;
 if(x % 2 == 0)
 {
 ct++;
 }
 }while(x > 0);
End of Iteration # Value of X Value of CT
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Lab #7 – Programming Assignment
Due: Friday March 26, 2021 at 11:00pm (time local to West Lafayette, IN)
10 Points Possible
Problem: Given a non-negative decimal (base 10) integer value as input display the octal (base 8) equivalent. More
information on numbering systems can be found on page 1033 of your C programming text. The program is also expected
to display the change in odd and even digits between the two numbers (base 10 and base 8 equivalent).
• At no point in the process of solving this problem will a value greater than that which can be represented by an
int type will be input, generated, or output.
Example Execution #1 (one more odd digit and one less even digit in the octal equivalent):
Enter decimal value -> 123123
Octal equivalent: 360363
Odd digit change: +1
Even digit change: -1
Example Execution #2 (one more odd digit in the octal equivalent):
Enter decimal value -> 9
Octal equivalent: 11
Odd digit change: -1
Even digit change: 0
Example Execution #3:
Enter decimal value -> 123456
Octal equivalent: 361100
Odd digit change: 0
Even digit change: 0
Example Execution #4 (input validation expectations demonstrated):
Enter decimal value -> -3
Error! The decimal value provided should be non-negative.
Enter decimal value -> 24680
Octal equivalent: 60150
Odd digit change: -2
Even digit change: +2
Example Execution #5:
Enter decimal value -> 9999
Octal equivalent: 23417
Odd digit change: +1
Even digit change: -2
All course programming and documentation standards are in effect for this and each
assignment this semester. Please review this document!
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Additional Requirements:
1. Add the lab assignment header (vi shortcut hlb while in command mode) to the top of your program. An
appropriate description of your program must be included in the assignment header. Include the Purdue
University e-mail addresses of each contributing group member in the assignment header!
2. Each of the example executions provided for your reference represents a single execution of the program.
Your program must accept input and produce output exactly as demonstrated in the example executions. Your
program will be tested with the data seen in the example executions and an unknown number of additional tests
making use of reasonable data.
◦ Input validation requirements can be seen in the fourth example execution. Review the course notes
packet for course expectations of input validation.
3. For this assignment you will be required to implement the user-defined functions (from chapter 4). Failing to
follow course standards as they relate to good user-defined function use will result in a zero for this assignment.
4. Revisit course standards as it relates what makes for good use of user-defined functions, what is acceptable
to retain in the main function, and when passing parameters by address is appropriate.
◦ In many cases user-defined function use should result in a main function that only declares variables and
makes calls functions.
5. Course standards prohibit the use of programming concepts not yet introduced in lecture. For this assignment
you can consider all material in the first SIX chapters of the book, notes, and lectures to be acceptable for use.
◦ The use of arrays, including character pointers to represent string data, would violate requirements of this
assignment and result in no credit being awarded for your effort.
6. A program MUST compile, be submitted through the guru server prior to the posted due date to be considered
for partial credit. The submission script will reject the submission of any file that does not successfully compile
on the guru server. The C-file you submit must be named exactly: lab07.c
Course Programming and Documentation Standards Reminders:
• Code found inside the body of relevant selection and repetition constructs must be indented two additional spaces.
• Make use of { and } with all relevant selection and repetition constructs.
• See page 258 of your C programming text regarding the proper indentation for a switch construct.
• Note the standard related to control forcing statements found on page 15 of the course notes packet.
• Use the course function header (head_fx vi shortcut hfx while in command mode) for every user-defined
function in your program.
◦ List and comment all parameters to a function, one per line, in the course function header.
◦ All function declarations will appear in the global declaration section of your program.
◦ The user-defined function definitions will appear in your program after the main function.
• Maximize your use of symbolic/defined constants and minimize your use of literal constants.
• Indent all code found within the main and all user-defined functions exactly two spaces.
• Place a single space between all operators and operands.
• Comment all variables to the right of each declaration. Declare only one variable per line.
• Notice that several programs (see program 2-9 on pages 74-75) in the programming text use a single line
comment to indicate the start of the local declaration and executable statement sections of the main function.
◦ At no point during the semester should these two sections ever overlap. You might consider adopting this
habit of commenting the start of each section to help you avoid this mistake.
• Select meaningful identifiers (names) for all variables in your program.
• Do not single (or double) space the entire program, use blank lines when appropriate.
• There is no need to include example output with your submission.
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Auto-Grade Tool
• We have implemented what is being referred to as the auto-grade tool. At the time of a successful assignment
submission you may receive some feedback on your program in regards to course programming and
documentation standards. This feedback may include a potential deduction that you will receive once your
assignment is reviewed by your grader.
• It is expected that graders verify those notes identified by this tool to ensure that they are indeed applicable and
reasonable to the submission. Graders may make additional deductions for those standards not identified by the
new tool.
• We hope that this feedback helps with the enforcement of course standards, consistency in grading across
sections, and to encourage students to revise their work when problems are identified before the assignment
deadline passes. It is possible to resubmit an assignment for grading up to the advertised deadline. Only the final
successful submission is retained and evaluated.
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