Week 08 Laboratory Exercises

Objectives

  • working with multi file programs
  • working with structs and pointers
  • introducing linked lists
  • using memory allocation

Activities To Be Completed

The following is a list of all the activities available to complete this week...

Worth one mark in total:

  • list_print
  • list_insert_head
  • fractions

Worth half a mark in total:

  • list_contains
  • list_insert_tail

Worth half a mark in total:

  • list_insert_nth
  • list_reverse

For your interest, but not for marks:

  • student_becomes_teacher

Preparation

Before the lab you should re-read the relevant lecture slides and their accompanying examples.

Exercise
(●◌◌)
:

Print out the elements of a Linked List

Download list_print.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T3/activities/list_print/list_print.c .

Your task is to add code to this function in list_print.c:

// print a linked list in this format:
// 17 -> 34 -> 51 -> 68 -> X
void print(struct node *head) {

    // PUT YOUR CODE HERE
}
print is given one argument, head, which is the pointer to the first node in a linked list.

Add code to print so that it prints the elements in the list

For example if the linked list contains these 8 elements:

1, 7, 8, 9, 13, 19, 21, 42

print should print 1 -> 7 -> 8 -> 9 -> 13 -> 19 -> 21 -> 42 -> X

Testing

list_print.c also contains a main function which allows you to test your print function.

This main function:

  • converts the command-line arguments to a linked list
  • assigns a pointer to the first node in the linked list to head
  • calls list_print(head)

Do not change this main function. If you want to change it, you have misread the question.

Your list_print function will be called directly in marking. The main function is only to let you test your list_print function

Here is how you use main function allows you to test list_print:

dcc list_print.c -o list_print
./list_print 1 2 4 8 16 32 64 128 256
1 -> 2 -> 4 -> 8 -> 16 -> 32 -> 64 -> 128 -> 256 -> X
./list_print 2 4 6 5 8 9
2 -> 4 -> 6 -> 5 -> 8 -> 9 -> X
./list_print 42 4
42 -> 4 -> X
./list_print 43
43 -> X
./list_print
X

Assumptions/Restrictions/Clarifications.

print should not change the linked list it is given. Your function should not change the next or data fields of list nodes.

print should not use arrays.

print should not call malloc.

print should not call scanf (or getchar or fgets).

Do not change the supplied main function. It will not be tested or marked.

You can run an automated code style checker using the following command:
1511 style list_print.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest list_print

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab08_list_print list_print.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 08 November 20:00 to obtain the marks for this lab exercise.

Exercise
(●◌◌)
:

Insert an element at the head of a Linked List

Download list_insert_head.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T3/activities/list_insert_head/list_insert_head.c .

Your task is to add code to this function in list_insert_head.c:

// Insert a new node containing value at the start of the linked list.
// The head of the new list is returned.
struct node *insert_head(int value, struct node *head) {

    // PUT YOUR CODE HERE (change the next line!)
    return NULL;

}
insert_head is given two arguments, value and head. value is an int. head is the pointer to the first node in a linked list.

Add code to insert_head so that it creates a new list node (using malloc) containing value and places it at the start of the list.

insert_head should return a pointer to the new list.

For example if value is 12 and the linked list contains these 3 elements:

16, 7, 8

insert_head should return a pointer to a list with these elements:

12, 16, 7, 8

Testing

list_insert_head.c also contains a main function which allows you to test your insert_head function.

This main function:

  • converts the command-line arguments to a linked list
  • assigns a pointer to the first node in the linked list to head
  • reads a single integer from standard input and assigns it to value
  • calls insert_head(value, head)
  • prints the result.

Do not change this main function. If you want to change it, you have misread the question.

Your insert_head function will be called directly in marking. The main function is only to let you test your insert_head function

dcc list_insert_head.c -o list_insert_head
./list_insert_head 16 7 8
12
[12, 16, 7, 8]
./list_insert_head 16
42
[42, 16]
./list_insert_head
2
[2]

Assumptions/Restrictions/Clarifications.

insert_head should not use arrays.

insert_head should not call scanf (or getchar or fgets).

insert_head should not print anything. It should not call printf.

Do not change the supplied main function. It will not be tested or marked.

You can run an automated code style checker using the following command:
1511 style list_insert_head.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest list_insert_head

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab08_list_insert_head list_insert_head.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 08 November 20:00 to obtain the marks for this lab exercise.

Exercise
(●◌◌)
:

Writing your own fractions library

Implement the functions, detailed in fractions.h, in fractions.c. You can use main.c to test your program.

You must not change fractions.h and main.c. You will only be submitting fractions.c.

Download fractions.h here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T3/activities/fractions/fractions.h .

Download fractions.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T3/activities/fractions/fractions.c .

Download main.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T3/activities/fractions/main.c .

To complete this activity, you must read the descriptions of each function in fractions.h and then complete these functions in fractions.c. This is similar to how we expect you to complete assignment 2. All assumptions and clarifications will be found in the H file.

When complete, your program will behave like this.

dcc -o fractions fractions.c main.c
./fractions convert 2/3
2 / 3 converts to 0.666667
./fractions convert 10/7
10 / 7 converts to 1.428571
./fractions add 1/2 1/3
1 / 2 + 1 / 3 = 5 / 6
./fractions add 2/10 1/5
2 / 10 + 1 / 5 = 2 / 5
You can run an automated code style checker using the following command:
1511 style fractions.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest fractions

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab08_fractions fractions.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 08 November 20:00 to obtain the marks for this lab exercise.

Exercise
(●●◌)
:

Find an element in a Linked List

Download list_contains.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T3/activities/list_contains/list_contains.c .

Your task is to add code to this function in list_contains.c:

// Return 1 if value occurs in linked list, 0 otherwise
int contains(char *value, struct node *head) {

    // PUT YOUR CODE HERE (change the next line!)
    return 42;
}
contains is given two arguments, a string value and head, which is the pointer to the first node in a linked list.

Add code to contains so that its returns 1 if value occurs in the linked and otherwise it returns 0.

For example if the linked list contains these 7 elements:

"mozarella" "pepperoni" "basil" "ham" "tomato bacon" "cheesy-crust" "bocconcini"

and contains is called with value of "mozarella",

contains should return 1.

Testing

list_contains.c also contains a main function which allows you to test your contains function.

This main function:

  • converts the command-line arguments to a linked list
  • assigns a pointer to the first node in the linked list to head
  • reads a single string from standard input and assigns it to value
  • calls list_contains(value, head)
  • prints the result.

Do not change this main function. If you want to change it, you have misread the question.

Your list_contains function will be called directly in marking. The main function is only to let you test your list_contains function

Here is how you use main function allows you to test list_contains:

dcc list_contains.c -o list_contains
./list_contains pepperoni ham basil capsicum
basil
1
./list_contains pepperoni ham basil capsicum
mozarella
0
./list_contains chicken mushroom mushroom pizza-sauce
mushroom
1
./list_contains tomato bacon capsicum mushroom
pepperoni
0
./list_contains
tomato
0

Assumptions/Restrictions/Clarifications.

String matching is case sensitive. "Tomato" does not match "tomato". No strings will have the space character in them (either from command line arguments or the single input string). contains should return a single integer.

contains should not change the linked list it is given. Your function should not change the next or data fields of list nodes.

contains should not use arrays.

contains should not call malloc.

contains should not call scanf (or getchar or fgets).

contains should not print anything. It should not call printf.

Do not change the supplied main function. It will not be tested or marked.

You can run an automated code style checker using the following command:
1511 style list_contains.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest list_contains

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab08_list_contains list_contains.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 08 November 20:00 to obtain the marks for this lab exercise.

Exercise
(●●◌)
:

Insert an element at the tail of a Linked List

Download list_insert_tail.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T3/activities/list_insert_tail/list_insert_tail.c .

Your task is to add code to this function in list_insert_tail.c:

// Insert a new node containing value at the end of the linked list.
// The head of the new list is returned.
struct node *insert_tail(int value, struct node *head) {

    // PUT YOUR CODE HERE (change the next line!)
    return NULL;

}
insert_tail is given two arguments, value and head. value is an int. head is the pointer to the first node in a linked list.

Add code to insert_tail so that it creates a new list node (using malloc) containing value and places it at the end of the list.

insert_tail should return a pointer to the new list.

For example if value is 12 and the linked list contains these 3 elements:

16, 7, 8

insert_tail should return a pointer to a list with these elements:

16, 7, 8, 12

Testing

list_insert_tail.c also contains a main function which allows you to test your insert_tail function.

This main function:

  • converts the command-line arguments to a linked list
  • assigns a pointer to the first node in the linked list to head
  • reads a single integer from standard input and assigns it to value
  • calls insert_tail(value, head)
  • prints the result.

Do not change this main function. If you want to change it, you have misread the question.

Your insert_tail function will be called directly in marking. The main function is only to let you test your insert_tail function

dcc list_insert_tail.c -o list_insert_tail
./list_insert_tail 16 7 8
12
[16, 7, 8, 12]
./list_insert_tail 16
42
[16, 42]
./list_insert_tail
2
[2]

Assumptions/Restrictions/Clarifications.

insert_tail should not use arrays.

insert_tail should not call scanf (or getchar or fgets).

insert_tail should not print anything. It should not call printf.

Do not change the supplied main function. It will not be tested or marked.

You can run an automated code style checker using the following command:
1511 style list_insert_tail.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest list_insert_tail

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab08_list_insert_tail list_insert_tail.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 08 November 20:00 to obtain the marks for this lab exercise.

Exercise
(●●●)
:

Insert into the nth position in a Linked List

Download list_insert_nth.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T3/activities/list_insert_nth/list_insert_nth.c .

Your task is to add code to this function in list_insert_nth.c:

// Insert a new node containing value at position n of the linked list.
// if n == 0, node is inserted at start of list
// if n >= length of list, node is appended at end of list
// The head of the new list is returned.
struct node *insert_nth(int n, int value, struct node *head) {

    // PUT YOUR CODE HERE (change the next line!)
    return NULL;

}
insert_nth is given three arguments, n, value and head. n is an int. value is an int. head is the pointer to the first node in a linked list.

Add code to insert_nth so that it creates a new list node (using malloc) containing value and places it before position n of the list.

The elements are counted in the same manner as array elements (zero-based), so the first element in the list is regarded as at position 0, the second element position 1 and so on.

If there are less than n elements in the list, the new list node should be appended to the end of the list.

insert_nth should return a pointer to the new list.

For example if n is 1 and value is 12 and the linked list contains these 3 elements:

16, 7, 8

insert_nth should return a pointer to a list with these elements:

16, 12, 7, 8

Testing

list_insert_nth.c also contains a main function which allows you to test your insert_nth function.

This main function:

  • converts the command-line arguments to a linked list
  • assigns a pointer to the first node in the linked list to head
  • reads an integer from standard input and assigns it to n
  • reads a second integer from standard input and assigns it to value
  • calls insert_nth(n, value, head)
  • prints the result.

Do not change this main function. If you want to change it, you have misread the question.

Your insert_nth function will be called directly in marking. The main function is only to let you test your insert_nth function

dcc list_insert_nth.c -o list_insert_nth
./list_insert_nth 16 7 8
0
12
[12, 16, 7, 8]
./list_insert_nth 16 7 8
1
12
[16, 12, 7, 8]
./list_insert_nth 16 7 8
2
12
[16, 7, 12, 8]
./list_insert_nth 16 7 8
3
12
[16, 7, 8, 12]
./list_insert_nth 16 7 8
42
12
[16, 7, 8, 12]
./list_insert_nth 42
0
16
[16, 42]
./list_insert_nth
0
2
[2]
./list_insert_nth
10
2
[2]

Assumptions/Restrictions/Clarifications.

insert_nth should not use arrays.

insert_nth should not call scanf (or getchar or fgets).

insert_nth should not print anything. It should not call printf.

Do not change the supplied main function. It will not be tested or marked.

You can run an automated code style checker using the following command:
1511 style list_insert_nth.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest list_insert_nth

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab08_list_insert_nth list_insert_nth.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 08 November 20:00 to obtain the marks for this lab exercise.

Exercise
(●●●)
:

Reverse a Linked List

Download list_reverse.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T3/activities/list_reverse/list_reverse.c .

Your task is to add code to this function in list_reverse.c:

//
// Place the list pointed to by head into reverse order.
// The head of the list is returned.
//
struct node *reverse(struct node *head) {

    // PUT YOUR CODE HERE (change the next line!)
    return NULL;

}
Note list_reverse.c uses the following familiar data type:
struct node {
    struct node *next;
    int          data;
};
list_reverse is given one argument, head, which is the pointer to the first node in the linked list.

Add code to reverse which rearranges the list to be in reverse order.

reverse should return a pointer to the new list.

reverse must rearrange the list by changing the next fields of nodes.

reverse must not change the data fields of nodes.

For example if the linked list contains these 8 elements:

16, 7, 8, 12, 13, 19, 21, 12

reverse should return a pointer to a list with these elements:

12, 21, 19, 13, 12, 8, 7, 16

Testing

list_reverse.c also contains a main function which allows you to test your list_reverse function.

This main function:

  • converts the command-line arguments to a linked list
  • assigns a pointer to the first node in the linked list to head
  • calls reverse(head)
  • prints the result.

Do not change this main function. If you want to change it, you have misread the question.

Your list_reverse function will be called directly in marking. The main function is only to let you test your list_reverse function

cp -n /web/cs1511/21T3/activities/list_reverse/list_reverse.c .
dcc list_reverse.c -o list_reverse
./list_reverse 16 7 8 12 13 19 21 12
[12, 21, 19, 13, 12, 8, 7, 16]
./list_reverse 2 4 6 2 4 6
[6, 4, 2, 6, 4, 2]
./list_reverse 42
[42]
./list_reverse
[]

Assumptions/Restrictions/Clarifications.

list_reverse should not change the data fields of list nodes.

list_reverse should not use arrays.

list_reverse should not call malloc.

list_reverse should not call scanf (or getchar or fgets).

list_reverse should not print anything. It should not call printf.

Do not change the supplied main function. It will not be tested or marked.

You can run an automated code style checker using the following command:
1511 style list_reverse.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest list_reverse

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab08_list_reverse list_reverse.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 08 November 20:00 to obtain the marks for this lab exercise.

Exercise
(☠)
:

The Student Becomes The Teacher

Welcome to Week 8 of COMP1511. The end of term is in sight!

If you've come this far in this week's lab, you're probably feeling pretty confident in some aspects of the course! So, why not help yourself and your peers by creating a resource that teaches a concept in COMP1511?

Details

For this exercise, create content that helps teach a concept in COMP1511. This could be a video, a program, a blog, or anything else you can think of.

If you're not sure what to do, chat to your tutor for inspiration!

When you're done, post your creation on the forum. We may also post some of the resources you share in one place, so everyone can benefit from them!

If you're interested in becoming a tutor for a COMP course, this can also be great practice, as one requirement we have for tutoring applicants is making a short explainer video.

This is the last challenge exercise for the term! Next week, we will have this exercise as well; so you'll have two weeks to complete this :)

You can run an automated code style checker using the following command:
1511 style student_becomes_teacher.c

Submission

When you are finished each exercises make sure you submit your work by running give.

You can run give multiple times. Only your last submission will be marked.

Don't submit any exercises you haven't attempted.

If you are working at home, you may find it more convenient to upload your work via give's web interface.

Remember you have until Week 9 Monday 20:00 to submit your work.

You cannot obtain marks by e-mailing your code to tutors or lecturers.

You check the files you have submitted here.

Automarking will be run by the lecturer several days after the submission deadline, using test cases different to those autotest runs for you. (Hint: do your own testing as well as running autotest.)

After automarking is run by the lecturer you can view your results here. The resulting mark will also be available via give's web interface.

Lab Marks

When all components of a lab are automarked you should be able to view the the marks via give's web interface or by running this command on a CSE machine:

1511 classrun -sturec