While the focus of this task is on the declaration and usage of pointers in data
manipulation, remember to deliver your task in a good quality with proper
coding convention and practice under considerations of the following but not
limited to: comments, indentation, snake_case, and meaningful identifiers
whenever appropriate.
SIT102 Introduction to Programming
Pass Task 9.2: Data Pass by Pointers
We are approaching to the end of the trimester. This 9.2P TASK due and MILESTONE due are NOT
able to be postponed beyond the trimester. We highly encourage you submit your 9.2P as soon as you
could such that there is sufficient time for both the teaching team reviewing your on-time submission and
you fixing your work (if necessary) by the MILESTONE due (See 9.MP task for details)
Please note: If you need to apply an extension for 9.2P, OnTrack will only auto-grant you a few days up
to 23 May 2022. Please also note there is no room for any extension on 9.MP (MILESTONE).
Overview of 9.2P task
Pointers are one of efficient building blocks in a C++ program to support its dynamic allocation
outines. After discussions in this week’s topics about fundamental of pointers including its nature in
terms of the data fields, data referencing and dereferencing rationales and operations, as well as data
access and pointers challenges, this task enables you to apply, demonstrate and reinforce your
understanding and associated programming skills on pointers usage and data manipulation by various
forms of illustrations and works including codes, quick answers, screenshots, and drawings.
Submission Details
Follow the instructions on the following pages, weekly videos and class contents to create a C++
program to explore the usage of pointers and passing data by pointer.
Submit the following files to OnTrack.
• Your answers to the associated questions (9.2P Answers.docx) in PDF
• Your C++ program code with your answer to both part A and part B
Instructions – Resources
1. Obtain the given code snippet to start with in Resources.zip. Note: this task requires you to
demonstrate your understanding on the variables’ nature and their relationship so that they are not
named based on their meanings in the given code snippet. However, maintain good coding
convention whenever appropriate in your new implementation.
2. The given instructions and implementation in the code snippet demonstrates how data value and
address of ordinary variables (i.e. variables d, and s) in different types are obtained and printed
onto the Terminal using
:: write/write_line. Fig. 1 shows you the sample execution
outcome of the given start-up code snippet. They are the quick recap of active class – week 9
contents for you to begin with.
Fig. 1: Execution outcome of the given start-up code snippet.
3. For you starting off Part B, you are also provided the implementation and programming logic for
void swap_pass_by_value(string s, string name) where it reminds you how pass-by-value is
applied and provides you with a simple swap (two values) mechanism in the code snippet. Note
that swap_pass_by_value(…) is called at the end of pointer_var_info(). That is the entry point for
your Part B with the objective of exploring pass-by-value and pass-by-pointer.
4. Get the questions (in 9.2P Answers.docx) in Resources.zip along with you. Following the
instructions, you would showcase some of your workout there as parts of your submission.
Instructions – Your tasks
Part A:
1. In order to complete the table in 9.2P Answers.docx, you are required to
a. demonstrate the co
ect usage of the declared/defined pointer variables in C++ (i.e. variables
x and z). Also refer to Fig. 1 and the README code comments in the start-up snippet.
. obtain the requested information from the pointer variables
i. Memory location of the variable
ii. Value stored in the co
esponding variable
iii. Variable name
c. show all of the above information onto the Terminal
(You may choose to make use of either ::cout or :: write for displaying
information to the Terminal).
2. Besides your code implementation, you are also required to show the execution Terminal output of
your program and answer all the questions in Resources.zip.
Part B:
1. In the start-up code snippet, variables string s, *z, and name have been declared and defined for
you in pointer_var_info(). You are now required to modify the code to ask the user to input a name
and save it in string name, as a real-time data input collection instead of having a pre-defined value
for string name.
2. Then declare a new pointer variable that points to (is referencing to) string name. Make sure your
implementation works properly.
3. Keep implementing your program to accomplish the following:
a. Demonstrate that your program is capable of swapping two input values by using pass-by-
pointer approach under the following declaration
 void swap_pass_by_pointer(string *z, string *)
. The same actions as in the given swap_pass_by_value(…) as
i. 1. Print the passed in values to Terminal
ii. 2. Apply a simple swap mechanism
iii. 3. Print the updated values to the Terminal just after the swap
should be conducted but the data should be passed in by pointers in your implementation.
c. For each declared variable, verify how their values are stored respectively inside and out of
the swap procedures. You should obtain similar outcomes as shown in Fig. 2 with your own
values. Since we are implementing them as procedures, as you can see, the pass-by-value
approach does not work. In contrast, the pass-by-pointer approach works as expected.
Fig. 2: Expected outcomes of values swapping by pass-by-value and pass-by-pointer.
4. After your implementation, go back to 9.2P Answers.docx, provide execution Terminal output of
your program, and answer all the questions there to comment different data passing approaches.
5. Make sure you have completed all task requirements. Save your 9.2P Answers.docx as a PDF.
Submit it together with your part A and part B code implementation in one single .cpp to OnTrack.
That’s all for the instructions. Good luck to your task!
Task Discussion
You tutor may ask you the following question(s) via OnTrack. You have to address them to
demonstrate your understanding of the concepts covered.
• Explain how pass-by-value, pass-by-reference, and pass-by-pointer work.
• Discuss the pros and cons of adopting the above three data-passing approaches.
• How would pointers help in dynamic memory allocation for data storage?
Overview of 9.2P task
Submission Details
Instructions – Resources
Instructions – Your tasks
Task Discussion
SIT102 – Introduction to Programming
Answers for 9.2P Data Pass by Pointers
Student Name:
Student ID:
Based on the given start-up code snippet in Resources.zip and your own implementation addressing the task requirements, provide your answers to the following questions.
Part A:
1. There are 4 variables declared in the given start-up code snippet. Complete the following table with the co
ect memory addresses and the stored value accordingly for each variable. You have to add in your implementation to the given code in order to obtain all the required information for those pointer variables (i.e. variables x and z).
Bear in mind, as discussed in the classes that those memory addresses are different from any illustration shown in this tasksheet and may also be different from your friends’ workout.
Memory location of the variable
(You may have different value, replace all contents here by your own value.)
Based on the given code, value stored in the variable
Variable name
XXXXXXXXXXBased on execution outcome shown in the tasksheet)
Replace this content by your own answe
7.99
d
SIT102
s
x
z
2. Provide the execution output of your modified program by a screenshot of your Terminal, which could fully verify your answers provided in the above question.
3. Depict the relationship of the above-mentioned FOUR variables - d, s, x, and z by a drawing in the style of hand execution that has been utilised since week 2 and week 9 classes.
Note 1: Make good use of an a
ow connecting memory locations (depicted by two boxes as shown) to illustrate the referencing/dereferencing direction. E.g. variable a is pointing to a memory location which stores the cu
ent value for variable b as shown below. This kind of drawing would be used by you to effectively demonstrate your understanding about relationship between variables and memory locations in Part B.
XXXXXXXXXXVariable a
Variable
Value stored in
Value stored in a
Note 2: Make sure you have filled in co
ect values/names in your drawing based on the given code.
Part B:
4. Provide the execution output of your Part B workout by a screenshot of your Terminal which could throw a scene for your following answers.
5. Depict the relationship of the following THREE variables - name, s, and temp by a hand execution drawing for the pass-by-value scenario. Show how the values are declared/defined, processed/changed from the beginning of the program execution to the end of this swap process.
6. Depict the relationship of the following FIVE variables - name, z, s, temp, and your newly declared pointer by a hand execution drawing for the pass-by-pointer scenario. Show how the values are declared/defined, processed/changed from the beginning of the program execution of this swap process.