CS 159 - Lab #11

CS 159 - Lab #11
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
April 30, 2021 at 11:00pm (LOCAL WEST LAFAYETTE, IN TIME). No late work will be accepted.
Weekly Quiz #11:
The weekly quiz will be available (Week 15 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 material from chapters 7, 9/10, 11, 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 evaluate submissions from multiple members of the same group to determine which submission is the
official submission of the group. 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?
◦ Work as a group on the written problems of this lab! The corresponding weekly quiz is the final one of the
semester and from many students this is the time of the semester when every point is meaningful!
◦ This assignment has a requirement to use dynamic memory allocation as introduced in lecture. Look to the
resources of the course for guidance. In CS 159 only a small part of the topic that is dynamic memory
allocation is introduced, there is so much more to this idea and external sources are likely to include many
techniques never introduced in the course.
◦ How many “arrays” are needed this problem? What are they?
1
(Task #1) - Solve the following problems related to material found in Chapters 9/10 and the course standards.
Statement True / False
Section 9.1
A pointer is a variable that stores an address as its value.
The value of a pointer variable can change during the execution of a program.
The proper initialization of a pointer variable will include an address on the right side of the assignment
operator with the pointer variable on the left.
The indirection operator (*) is a unary operator whose operand must be a pointer value.
The act of dereferencing a pointer variable permits access to the value at the memory location to which the
pointer variable points (or refers).
The asterisk character (*) is used in two different contexts for pointer variables; for declaration and for
dereferencing.
The indirection and address operators are the inverse of each other and when combined in an expression
they cancel each other.
Working with an uninitialized pointer variable is a logical error.
Section 9.2
Every time we want a called function to access a variable in the calling function we pass the address of that
variable to the called function.
A user-defined function may be declared to return a pointer value.
Section 10.1
The name of an array is a pointer constant to its first element.
The dereference of an array name is the value of its first element.
The name of an integer array can be assigned to an integer pointer variable.
Section 10.2 – only concerned with one-dimensional arrays
When adding an integer to the name of an array the result is a value that corresponds to another index
location.
The size of an element is determined by the type of the pointer.
The following expressions are identical for the array a and integer n: *(a + n) and a[n]
The following expressions are identical for the array a and integer n: (a + n) and &a[n]
The following code segment uses pointer arithmetic to access and display the contents of the array.
 int i;
 int a[5] = {1, 3, 5, 2, 4};
 for(i = 0; i < 5; i++)
 {
 printf("%d ", *(a + i));
 }
 printf("\n");
2
Solve the following problems related to material found in Chapters 9/10 and the course standards.
Statement True or False
Section 10.3
When a whole array is passed to a function the called function can declare the array using the traditional
indexing notation [ ] or as a simple pointer variable.
Section 10.4
The C programming language provides two options for requesting memory, static allocation and dynamic
allocation.
Static memory allocation requires that the declaration and definition of the memory be fully specified in
the source program.
Dynamic memory allocation uses predefined functions to allocate memory for data while the program is
running.
All of the memory management functions are found in the standard library (stdlib.h).
The malloc function allocates a block of memory that contains the number of bytes specified in its
parameter.
The memory allocated as a result of the malloc function is not initialized and we should assume that it
will contain unknown values.
If we need to know the size of any data type the sizeof operator will give us the exact size in bytes.
The malloc function returns the starting address of the memory allocated.
The result of the malloc function is assigned to a pointer variable.
Solve the following problems related to material found in Chapter 7 and the course standards.
Statement True or False
If using an external file (via a file pointer) for input to a program then all input for the program must
come from the external source.
The value returned from the fopen function is used to initialize a file pointer.
The name of the external file being accessed is case insensitive when referenced in the fopen function
call.
The name of the external file is the parameter to the fclose function.
The fclose function can only be used to a close a connection that has been successfully opened.
The fscanf and fprintf functions reference the name of the file pointer but NOT the name of the
external file (as one of its parameters).
When the file pointer stores a value equal to zero it means the external file failed to open as expected.
A file pointer used to read external data into a program should always be compared with an error value
to determine the data file was opened as expected before allowing the program to continue.
The value returned from the fscanf function is the data value that was read from the external file.
The value of a file pointer must be returned when making use of a user-defined function to open an
external file. [In other words, file pointers ARE NOT passed by address.]
A value of the FILE* type cannot be used as a parameter to a user-defined function.
The EOF constant needs to be defined by the programmer before it can be used in your program.
3
Solve the following problems related to material found in Chapter 11 and the course standards.
Statement True or False
Section 11.1
A string is a series of characters treated as a unit.
A character known as a delimiter can be stored within a string to mark the end of the string data.
Section 11.2
A string is stored in a character array.
A delimiter (null) character is used by the standard string functions to detect the end of the string data.
Section 11.5
The strlen function from string.h will return the total number of characters in the array up to and
including the delimiter (null) character.
The strcpy function will copy the contents of the first character array parameter into the second.
If the two strings being compared by the strcmp function store the same data then the value returned
will be one.
Lab #11 – Programming Assignment
Due: Friday April 30, 2021 at 11:00pm (time local to West Lafayette, IN)
10 Points Possible
Problem: Given a positive integer representing the size of an integer data set, accept input of that data set, and display
the data sorted by odd and even with one additional requirement, an index that stores an odd value at the time of input
must store an odd value after the data is sorted with the same requirement holding for even values.
Example data input with set size of ten: {10, 8, 9, 7, 6, 4, 5, 3, 2, 1}
Even values are found at indexes: 0, 1, 4, 5, 8
Odd values are found at indexes: 2, 3, 6, 7, 9
Final result after odd and data values are sorted: {2, 4, 1, 3, 6, 8, 5, 7, 10, 9}
Other Requirements:
• The size of the data set is unknown until the program is running. This will necessitate the use of pointers and the
malloc function to create all of the arrays in your solution.
• Excessively large arrays or extra unnecessary arrays will be consider a deduction in the technique score when
your program is evaluated.
Example Execution #1 (described in example above):
Enter data set size -> 10
Enter 10 integer values -> 10 8 9 7 6 4 5 3 2 1
Final data set order: 2 4 1 3 6 8 5 7 10 9
All course programming and documentation standards are in effect for this and each
assignment this semester. Please review this document!
4
Example Execution #2:
Enter data set size -> 12
Enter 12 integer values -> 12 10 8 6 4 2 11 9 7 5 3 1
Final data set order: 2 4 6 8 10 12 1 3 5 7 9 11
Example Execution #3:
Enter data set size -> 9
Enter 9 integer values -> 17 15 13 11 9 7 5 3 1
Final data set order: 1 3 5 7 9 11 13 15 17
Example Execution #4:
Enter data set size -> 14
Enter 14 integer values -> 20 18 16 14 12 10 9 22 24 26 28 8 6 4
Final data set order: 4 6 8 10 12 14 9 16 18 20 22 24 26 28
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 may be tested with the data seen in the example executions and an unknown number of additional tests
making use of reasonable data.
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.
Good function design will limit each function to a single task, eliminate redundant logic in the program, and
maximize re-use of functions within a program.
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 userdefined function use should result in a main function that only declares variables and makes calls functions.
Selection and repetition constructs in a main function are to facilitate the calling of 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 ten chapters of the book, notes, and lectures to be acceptable for use.
◦ It remains acceptable to use sorting logic and code from the course notes, lectures, and/or the official C
programming text of the course. Be sure to reference your source in the header of the user-defined
function and to bring all code up to course standards.
6. A program MUST compile, meet assignment requirements, and 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: lab11.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.
5
Course Programming and Documentation Standards (continued):
• 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.
• At no point during the semester should the local declaration and executable statement sections of a function ever
overlap.
• Select meaningful identifiers (names) for all variables in your program.
• Do not single (or double) space the entire program, use blank lines when appropriate.
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.
6