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

cp -n /import/reed/A/dp1091/public_html/24T3/activities/mallocd_array/mallocd_array.c .

The main function has already been written for you. You must not modify it in any way.

Examples

dcc mallocd_array.c -o mallocd_array
./mallocd_array
Enter size: 5
Enter 5 integers:
1
2
3
4
5
The average of all values in the array is: 3.00
./mallocd_array
Enter size: 1
Enter 1 integers:
10
The average of all values in the array is: 10.00
./mallocd_array
Enter size: 3
Enter 3 integers:
5
-4
-3
The average of all values in the array is: -0.67

Assumptions/Restrictions/Clarifications

• You do not need to handle memory leaks for this exercise. i.e. You should not call free
• All inputs be of the correct type

1091 style mallocd_array.c
    

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

1091 autotest mallocd_array

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

give dp1091 lab10_mallocd_array mallocd_array.c
    

You must run give before Monday 04 November 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

// Written by lorenzo lee solano
// June, 2022

#include <stdio.h>
#include <stdlib.h>

//////////////// DO NOT CHANGE ANY OF THE CODE BELOW HERE //////////////////
int *scan_array(int size);
double calculate_average(int *array, int size);

int main (void) {

    int size;
    printf("Enter size: ");
    scanf(" %d", &size);
    if (size <= 0) {
        printf("Invalid Size\n");
        return 1;
    }

    printf("Enter %d integers:\n", size);
    int *array = scan_array(size);

    printf("The average of all values in the array is: %.2lf\n", 
           calculate_average(array, size));

    return 0;
}
//////////////// DO NOT CHANGE ANY OF THE CODE ABOVE HERE //////////////////

////////////////////////////////////////////////////////////////////////////
///////////////////// ONLY WRITE CODE BELOW HERE ///////////////////////////
////////////////////////////////////////////////////////////////////////////

// A function which scans in `size` integers and stores them into a 
// malloc'd array.
// returns: a pointer to the malloc'd array
int *scan_array(int size) {
    int i = 0;
    int *array = malloc(sizeof(int) * size);
    while (i < size) {
        scanf(" %d", &array[i]);
        i++;
    }

    return array;
}

// Given an integer array and it's size, 
// returns the sum of all elements inside the array, divided by the size of the
// array.
double calculate_average(int *array, int size) {
    int i = 0;
    int sum = 0;
    while (i < size ) {
        sum += array[i];
        i++;
    }
    return 1.0 * sum/size;
}

////////////////////////////////////////////////////////////////////////////
///////////////////// ONLY WRITE CODE ABOVE HERE ///////////////////////////
////////////////////////////////////////////////////////////////////////////

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

cp -n /import/reed/A/dp1091/public_html/24T3/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.

Your program will be supplied up to 50 integers, which will be put into a linked list that is passed to the print.

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

(including the X)

Testing

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

This main function:

• converts the input from terminal into a linked list
• assigns a pointer to the first node in the linked list to head
• calls list_print(head)

Do not change this 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.

Examples

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

• You can assume the input will never be more than 50 integers.
• 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.

1091 style list_print.c
    

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

1091 autotest list_print

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

give dp1091 lab10_list_print list_print.c
    

You must run give before Monday 04 November 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#define MAX_LEN 50

struct node {
    struct node *next;
    int          data;
};

void print(struct node *head);
struct node *array_to_list(int len, int num_array[]);

int main(void) {
    // create linked list from input
    int input_arr[MAX_LEN] = {0};
    int total_num = 0;
    int input_num;
    while (scanf(" %d", &input_num) == 1) {
        input_arr[total_num] = input_num;
        total_num++;
    }
    struct node *head = array_to_list(total_num, input_arr);

    print(head);

    return 0;
}

// Solution \/
////////////////////////////////////////////////////////////////////////////////
//  print a linked list in this format:
// 17 -> 34 -> 51 -> 68 -> X
void print(struct node *head) {
    struct node *n = head;
    while (n != NULL) {
        printf("%d -> ", n->data);
        n = n->next;
    }
    printf("X\n");
}
////////////////////////////////////////////////////////////////////////////////

// create linked list from array of strings
struct node *array_to_list(int len, int num_array[]) {
    struct node *head = NULL;
    for (int i = len - 1; i >= 0; i = i - 1) {
        struct node *n = malloc(sizeof (struct node));
        assert(n != NULL);
        n->next = head;
        n->data = num_array[i];
        head = n;
    }
    return head;
}

#include <stdio.h>
#include <assert.h>

struct node {
    struct node *next;
    int          data;
};

// print a linked list in this format:
// 17 -> 34 -> 51 -> 68 -> X
void print(struct node *head) {
    if (head == NULL) {
        printf("X\n");
    }
    printf("%d -> ", head->data);
    print(head->next);
}

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

cp -n /import/reed/A/dp1091/public_html/24T3/activities/list_length/list_length.c .

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

// Return the length of the linked list pointed by head
int length(struct node *head) {

    // PUT YOUR CODE HERE (change the next line!)
    return 42;

}

For this exercise, you will be given a linked list nodes containing integers, shown below.

struct node {
    struct node *next;
    int          data;
};

Your job is to complete the length function.

length is given one argument, head, which is the pointer to the first node in a linked list.

Add code to length so that its returns the length of the list.

For example if the linked list contains these 8 elements:

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

length should return 8.

Testing

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

This main function:

1. scans in number of items in the list, and its values; to create a linked list,
2. assigns a pointer to the first node in the linked list to head,
3. calls list_length(head), then
4. prints the result.

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

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

Examples

dcc list_length.c -o list_length
./list_length 
How many numbers in initial list?: 9
1 2 3 6 5 4 9 9 0
Counted 9 elements in linked list.
./list_length
How many numbers in initial list?: 6
1 2 3 6 5 4
Counted 6 elements in linked list.
./list_length
How many numbers in initial list?: 5
1 2 3 4 5
Counted 5 elements in linked list.
./list_length 
How many numbers in initial list?: 2
42 4
Counted 2 elements in linked list.
./list_length
How many numbers in initial list?: 0
Counted 0 elements in linked list.

Assumptions/Restrictions/Clarifications

• length should return a single integer
• length should not change the linked list it is given
• Your function should not change the next or data fields of list nodes
• length should not use arrays
• length should not call malloc
• length should not call scanf (or getchar or fgets)
• length should not print anything. It should not call printf
• Do not change the supplied main function. It will not be tested or marked

1091 style list_length.c
    

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

1091 autotest list_length

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

give dp1091 lab10_list_length list_length.c
    

You must run give before Monday 04 November 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

struct node {
    struct node *next;
    int          data;
};

int length(struct node *head);
struct node *strings_to_list(int len, char *strings[]);

int main(int argc, char *argv[]) {
    // create linked list from command line arguments
    struct node *head = strings_to_list(argc - 1, &argv[1]);

    int result = length(head);
    printf("%d\n", result);

    return 0;
}

// Return length of a linked list.
int length(struct node *head) {
    int len = 0;
    struct node *n = head;
    while (n != NULL) {
        len = len + 1;
        n = n->next;
    }
    return len;
}


// create linked list from array of strings
struct node *strings_to_list(int len, char *strings[]) {
    struct node *head = NULL;
    for (int i = len - 1; i >= 0; i = i - 1) {
        struct node *n = malloc(sizeof (struct node));
        assert(n != NULL);
        n->next = head;
        n->data = atoi(strings[i]);
        head = n;
    }
    return head;
}

#include <stdio.h>
#include <assert.h>

struct node {
    struct node *next;
    int          data;
};

// Return length of a linked list.
int length(struct node *head) {
    if (head == NULL) {
        return 0;
    }
    return 1 + length(head->next);
}

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

cp -n /import/reed/A/dp1091/public_html/24T3/activities/list_insert_head/list_insert_head.c .

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

// WRITE YOUR CODE INSIDE HERE ONLY!!!
// 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:

1. converts the first set of read integers to a linked list,
2. assigns a pointer to the first node in the linked list to head
3. reads another single integer from standard input and assigns it to value
4. calls insert_head(value, head)
5. prints the result.

Do not change this 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
How many numbers in initial list?: 
3
16 7 8
Enter number to insert to head: 
12
[12, 16, 7, 8]
./list_insert_head
How many numbers in initial list?: 
1
16
Enter number to insert to head: 
42
[42, 16]
./list_insert_head
How many numbers in initial list?: 
0
Enter number to insert to 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

1091 style list_insert_head.c
    

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

1091 autotest list_insert_head

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

give dp1091 lab10_list_insert_head list_insert_head.c
    

You must run give before Monday 04 November 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

struct node {
    struct node *next;
    int          data;
};

struct node *insert_head(int value, struct node *head);
struct node *array_to_list(int len, int array[]);
void print_list(struct node *head);

// DO NOT CHANGE THIS MAIN FUNCTION
#define MAX_INIT_LIST_LEN 100
int main() {
    // Need to read in a number of ints into an array
    printf("How many numbers in initial list?: ");
    int list_size = 0;
    scanf("%d", &list_size);
    int initial_elems[MAX_INIT_LIST_LEN] = {0};
    int n_read = 0;
    while (n_read < list_size && scanf("%d", &initial_elems[n_read])) {
        n_read++;
    }

    // create linked list from first set of inputs
    struct node *head = NULL;
    if (n_read > 0) {
        // list has elements
        head = array_to_list(n_read, initial_elems);
    }

    printf("Enter number to insert to head: ");
    int value = 0;
    scanf("%d", &value);
    struct node *new_head = insert_head(value, head);
    print_list(new_head);

    return 0;
}

// WRITE YOUR CODE INSIDE HERE ONLY!!!
// 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) {
    struct node *new_node = malloc(sizeof (struct node));
    if (new_node == NULL) {
        fprintf(stderr, "out of memory\n");
        exit(1);
    }
    new_node->data = value;
    new_node->next = head;
    return new_node;
}


// DO NOT CHANGE THIS FUNCTION
// create linked list from array of strings
struct node *array_to_list(int len, int array[]) {
    struct node *head = NULL;
    int i = len - 1;
    while (i >= 0) {
        struct node *n = malloc(sizeof (struct node));
        assert(n != NULL);
        n->next = head;
        n->data = array[i];
        head = n;
        i -= 1;
    }   
    return head;
}

// DO NOT CHANGE THIS FUNCTION
// print linked list
void print_list(struct node *head) {
    printf("[");    
    struct node *n = head;
    while (n != NULL) {
        // If you're getting an error here,
        // you have returned an invalid list
        printf("%d", n->data);
        if (n->next != NULL) {
            printf(", ");
        }
        n = n->next;
    }
    printf("]\n");
}

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

cp -n /import/reed/A/dp1091/public_html/24T3/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 it returns 1 if value occurs in the linked list and otherwise it returns 0.

For example if the linked list contains these 7 elements:

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

and contains is called with value of "mozzarella",

contains should return 1.

Testing

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

This main function:

1. Asks for how many strings will be in our list,
2. reads in and converts that n many strings to a linked list,
3. assigns a pointer to the first node in the linked list to head,
4. reads another single string from standard input and assigns it to value.
5. calls list_contains(value, head) and
6. prints the result.

Do not change this 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

Examples

dcc list_contains.c -o list_contains
./list_contains
How many strings in initial list?: 4
pepperoni
ham
basil
capsicum
Enter word to check contained: basil
1
./list_contains
How many strings in initial list?: 4
pepperoni
ham
basil
capsicum
Enter word to check contained: mozzarella
0
./list_contains 
How many strings in initial list?: 4
chicken
mushroom
mushroom
pizza-sauce
Enter word to check contained: mushroom
1
./list_contains
How many strings in initial list?: 4
tomato
bacon
capsicum
mushroom
Enter word to check contained: pepperoni
0
./list_contains
How many strings in initial list?: 0
Enter word to check contained: tomato
0

Assumptions/Restrictions/Clarifications

• String matching is case sensitive. "Tomato" does not match "tomato". No strings will have the space character in them
• 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.

1091 style list_contains.c
    

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

1091 autotest list_contains

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

give dp1091 lab10_list_contains list_contains.c
    

You must run give before Monday 04 November 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#define MAX_STRING_SIZE 1024
#define MAX_STRINGS 50

struct node {
    struct node *next;
    char         data[MAX_STRING_SIZE];
};

int contains(char *value, struct node *head);
struct node *strings_to_list(int len, char *strings[]);
void remove_newline(char *string);

// DO NOT CHANGE THIS MAIN FUNCTION


int main(void) {
    // Need to read in a number of ints into an array
    printf("How many strings in initial list?: ");
    int list_size = 0;
    scanf("%d ", &list_size);
    char *initial_elems[MAX_STRINGS] = {NULL};

    int i = 0;
    while (i < list_size) {
        //Allocate string:
        char *string = malloc(sizeof(char) * MAX_STRING_SIZE);
        // scan string
        fgets(string, MAX_STRING_SIZE, stdin);
        remove_newline(string);

        initial_elems[i] = string;
        i++;
    }

    printf("Enter word to check contained: ");

    // Read in word to check that contained inside
    char value[MAX_STRING_SIZE] = {'\0'};
    fgets(value, MAX_STRING_SIZE, stdin);
    remove_newline(value);

    // create linked list from inputs
    struct node *head = NULL;
    if (list_size > 0) {
        // list has elements
        head = strings_to_list(list_size, initial_elems);
    }

    int result = contains(value, head);
    printf("%d\n", result);

    return 0;
}




// Return 1 if value occurs in linked list, 0 otherwise
int contains(char *value, struct node *head) {
    struct node *curr = head;
    while (curr != NULL && strcmp(curr->data, value) != 0) {
        curr = curr->next;
    }

    if (curr == NULL) {
        return 0;
    }
    return 1;
}


// DO NOT CHANGE THIS FUNCTION
// create linked list from array of strings
struct node *strings_to_list(int len, char *strings[]) {
    struct node *head = NULL;
    int i = len - 1;
    while (i >= 0) {
        struct node *n = malloc(sizeof (struct node));
        assert(n != NULL);
        n->next = head;
        strcpy(n->data, strings[i]);
        head = n;
        i -= 1;
    }   
    return head;
}

// Strips newline off the end of a string.
void remove_newline(char *string) {
    int len = strlen(string);

    if (len > 0 && string[len - 1] == '\n') {
        string[len - 1] = '\0';
    }
}

#include <stdio.h>
#include <assert.h>

struct node {
    struct node *next;
    int          data;
};

// Return 1 if value occurs in linked list, 0 otherwise
int contains(int value, struct node *head) {
    if (head == NULL) {
        return 0;
    }
    return (head->data == value) || contains(value, head->next);
}

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

cp -n /import/reed/A/dp1091/public_html/24T3/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.
// Parameters:
//      `int value`         : The value to insert.
//      `struct list *list` : a struct * containing the head pointer of the 
//      linked list.
void insert_tail(int value, struct list *list) {
    // PUT YOUR CODE HERE
}

insert_tail is given two arguments:

• value is an int
• list is the pointer to a struct list which contains
• the head (a pointer to the first node) of the 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 nothing.

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

16, 7, 8

insert_tail should modify the linked list so that it now has 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:

1. Asks for the size of the initial linked list
2. converts the first set of scanned inputs to a linked list
3. stores the first node of the linked list in a struct list.
4. reads a single integer from standard input and assigns it to value
5. calls insert_tail(value, list)
6. 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

Examples

dcc list_insert_tail.c -o list_insert_tail
./list_insert_tail
How many numbers in initial list?: 3
16 7 8
Enter value to insert: 12
[16, 7, 8, 12]
./list_insert_tail
How many numbers in initial list?: 1
16
Enter value to insert: 42
[16, 42]
./list_insert_tail
How many numbers in initial list?: 0
Enter value to insert: 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

1091 style list_insert_tail.c
    

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

1091 autotest list_insert_tail

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

give dp1091 lab10_list_insert_tail list_insert_tail.c
    

You must run give before Monday 04 November 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

// DO NOT CHANGE THESE STRUCTS
struct list {
    struct node *head;
};

struct node {
    struct node *next;
    int          data;
};

void insert_tail(int value, struct list *list);
struct list *array_to_list(int len, int array[]);
void print_list(struct list *list);

struct node *last(struct node *head);
struct node *create_node(int data, struct node *next);

// DO NOT CHANGE THIS MAIN FUNCTION
#define MAX_INIT_LIST_LEN 100
int main() {
    // Need to read in a number of ints into an array
    printf("How many numbers in initial list?: ");
    int list_size = 0;
    scanf("%d", &list_size);
    int initial_elems[MAX_INIT_LIST_LEN] = {0};
    int n_read = 0;
    while (n_read < list_size && scanf("%d", &initial_elems[n_read])) {
        n_read++;
    }

    // create linked list from first set of inputs
    struct list *list = NULL;
        // list has elements
    list = array_to_list(n_read, initial_elems);


    printf("Enter value to insert: ");
    int value;
    scanf("%d", &value);
    insert_tail(value, list);
    print_list(list);

    return 0;
}


void insert_tail(int value, struct list *list) {
    struct node *new_node = malloc(sizeof (struct node));
    if (new_node == NULL) {
        fprintf(stderr, "out of memory\n");
        exit(1);
    }
    new_node->data = value;
    new_node->next = NULL;

    // empty list is a special case
    // new node is now the head of the now 1 element list
    if (list->head == NULL) {
        list->head = new_node;
    } else {
        struct node *l = last(list->head);
        l->next = new_node;

    }
}

// return pointer to last node in list
// NULL is returned if list is empty

struct node *last(struct node *head) {
    if (head == NULL) {
        return NULL;
    }

    struct node *n = head;
    while (n->next != NULL) {
        n = n->next;
    }
    return n;
}


// DO NOT CHANGE THIS FUNCTION
// create linked list from array of strings
struct list *array_to_list(int len, int array[]) {
    struct node *head = NULL;
    int i = len - 1;
    while (i >= 0) {
        struct node *n = malloc(sizeof (struct node));
        assert(n != NULL);
        n->next = head;
        n->data = array[i];
        head = n;
        i -= 1;
    }

    struct list *list = malloc(sizeof(struct list));
    list->head = head;
    return list;
}

// DO NOT CHANGE THIS FUNCTION
// print linked list
void print_list(struct list *list) {
    printf("[");    
    struct node *n = list->head;
    while (n != NULL) {
        // If you're getting an error here,
        // you have returned an invalid list
        printf("%d", n->data);
        if (n->next != NULL) {
            printf(", ");
        }
        n = n->next;
    }
    printf("]\n");
}

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

cp -n /import/reed/A/dp1091/public_html/24T3/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:

• takes in the size of the linked list,
• converts the input numbers to a linked list,
• assigns a pointer to the first node in the linked list to head,
• calls reverse(head) and
• prints the result.

Do not change this 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

Examples

dcc list_reverse.c -o list_reverse
./list_reverse
How many numbers in list?: 8
16 7 8 12 13 19 21 12
[12, 21, 19, 13, 12, 8, 7, 16]
./list_reverse
How many numbers in list?: 6
2 4 6 2 4 6
[6, 4, 2, 6, 4, 2]
./list_reverse 42
How many numbers in list?: 1
42
[42]
./list_reverse
How many numbers in list?: 0
[]

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

1091 style list_reverse.c
    

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

1091 autotest list_reverse

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

give dp1091 lab10_list_reverse list_reverse.c
    

You must run give before Monday 04 November 09:00 to obtain the marks for this lab exercise. Note that this is an individual exercise, the work you submit with give must be entirely your own.

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

struct node {
    struct node *next;
    int          data;
};

struct node *reverse(struct node *head);
struct node *array_to_list(int len, int array[]);
void print_list(struct node *head);

// DO NOT CHANGE THIS MAIN FUNCTION
#define MAX_INIT_LIST_LEN 100
int main() {
    // Need to read in a number of ints into an array
    printf("How many numbers in list?: ");
    int list_size = 0;
    scanf("%d", &list_size);
    int initial_elems[MAX_INIT_LIST_LEN] = {0};
    int n_read = 0;
    while (n_read < list_size && scanf("%d", &initial_elems[n_read])) {
        n_read++;
    }

    // create linked list from first set of inputs
    struct node *head = NULL;
    if (n_read > 0) {
        // list has elements
        head = array_to_list(n_read, initial_elems);
    }
    
    struct node *new_head = reverse(head);
    print_list(new_head);

    return 0;
}

// Place the list into reverse order.
// The head of the list is returned.

struct node *reverse(struct node *head) {
    if (head == NULL) {
        return NULL;
    }
    struct node *previous = NULL;
    struct node *x = head;
    while (x != NULL) {
        struct node *y = x->next;
        x->next = previous;
        previous = x;
        x = y;
    }
    return previous;
}

// DO NOT CHANGE THIS FUNCTION
// create linked list from array of strings
struct node *array_to_list(int len, int array[]) {
    struct node *head = NULL;
    int i = len - 1;
    while (i >= 0) {
        struct node *n = malloc(sizeof (struct node));
        assert(n != NULL);
        n->next = head;
        n->data = array[i];
        head = n;
        i -= 1;
    }   
    return head;
}

// print linked list
void print_list(struct node *head) {
    printf("[");

    for (struct node *n = head; n != NULL; n = n->next) {
        // If you're getting an error here,
        // you have returned an invalid list
        printf("%d", n->data);
        if (n->next != NULL) {
            printf(", ");
        }
    }
    printf("]\n");
}

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

struct node {
    struct node *next;
    int          data;
};

// Place the list into reverse order.
// The head of the list is returned.

struct node *reverse(struct node *head) {
    // lists of 0 or 1 node don't need to be changed
    if (head == NULL || head->next == NULL) {
        return head;
    }

    //reverse rest of list
    struct node *new_head = reverse(head->next);

    // head->next will be the last element in the reversed rest of list
    // append head to it
    head->next->next = head;
    head->next = NULL;

    return new_head;
}

Copy the program debug_product.c from the course account to your directory by typing (make sure you type the dot at the end):

cp ~dp1091/public_html/24T3/activities/debug_product/debug_product.c .

Note that this exercise is not marked or worth marks!

Debugging Tips!

Some debugging tips for you:

• dcc output - as you run into issues, dcc will point you to where the errors are. Remember that dcc gives you the line number the issue is on, and will give some sort of explanation. Make sure you read everything dcc gives you. Sometimes we get “errors carried forward”, so find your first error, fix that, then recompile.
• print statements - sometimes it can be handy to see if the flow of your code puts you in the spot you expect it to be (ie. inside the right if statement, or going through a loop the correct amount of times). A quick way you can check this is by putting print statements in your code for testing purposes, like "the value of x is %d and y is %d". This lets you check that you got against what you expected.
• DPST1091 debugging guide - https://cgi.cse.unsw.edu.au/~dp1091/23T3/resources/debugging_guide.html

The Task

This exercise takes integers as command line arguments and calculates their cumulative product. However, if the number is 0 or not an integer, it is not added to the cumulative product of command line arguments. Currently it has some issues - it is your job to figure them out and fix the code.

Examples

dcc debug_product.c -o debug_product
./debug_product 0 1 2 3 4 5
Product: 120
./debug_product -5 1 -1 -2
Product: -10
./debug_product 100 these are my arguments -2
Product: -200
./debug_product these are my command line arguments
Product: 0

Assumptions/Restrictions/Clarifications

• You may find the atoi() function in the C standard library (stdlib.h) useful.
• You may assume that argv[0] will always be the program name.

1091 style debug_product.c
    

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

1091 autotest debug_product

// debug_product.c
//
// Thir program calucuates the product of command line args
//
// Written by Sofia De Bellis (z5418801), on July 2023

#include <stdlib.h>
#include <stdio.h>

int main (int argc, char *argv[]) {
    int prod = 0;

    for (int i = 1; i < argc; i++) {
        if (atoi(argv[i]) != 0) {
            if (prod == 0) {
                prod = 1;
            }
            prod *= atoi(argv[i]);
        }
    }

    printf("Product: %d\n", prod);
}

Copy the program debug_insert_second_last.c from the course account to your directory by typing (make sure you type the dot at the end):

cp ~dp1091/public_html/24T3/activities/debug_insert_second_last/debug_insert_second_last.c .

Note that this exercise is not marked or worth marks!

Debugging Tips!

Some debugging tips for you:

• dcc output - as you run into issues, dcc will point you to where the errors are. Remember that dcc gives you the line number the issue is on, and will give some sort of explanation. Make sure you read everything dcc gives you. Sometimes we get “errors carried forward”, so find your first error, fix that, then recompile.
• print statements - sometimes it can be handy to see if the flow of your code puts you in the spot you expect it to be (ie. inside the right if statement, or going through a loop the correct amount of times). A quick way you can check this is by putting print statements in your code for testing purposes, like "the value of x is %d and y is %d". This lets you check that you got against what you expected.
• DPST1091 debugging guide - https://cgi.cse.unsw.edu.au/~dp1091/23T3/resources/debugging_guide.html

The Task

This exercise takes in the length of a linked list, followed by the elements of the list. Then it takes in a single value to be inserted as the second last node of the list previously created.

For example if the existing list is 1 -> 2 -> 3 -> X and a node with value 4 is being inserted, after insertion the list is as follows: 1 -> 2 -> 4 -> 3 -> X. Note, the node containging the value 4 is inserted before the node containing the value 3 since the node containing the value 3 is at the tail (i.e the last node) of the list since it points at null.

Currently it has some issues when attempting to insert the value as the second last node in the list - it is your job to figure them out and fix the code.

Examples

dcc debug_insert_second_last.c -o debug_insert_second_last
./debug_insert_second_last
How many numbers in initial list?: 3
1 2 3
Enter the value to insert: 4
[1, 2, 4, 3]
./debug_insert_second_last
How many numbers in initial list?: 6
5 2 9 10 4 7
Enter the value to insert: 0
[5, 2, 9, 10, 4, 0, 7]
./debug_insert_second_last
How many numbers in initial list?: 1
23
Enter the value to insert: 5
[5, 23]
./debug_insert_second_last
How many numbers in initial list?: 0
Enter the value to insert: 4
[4]

Assumptions/Restrictions/Clarifications

• You do not need to edit the main(), array_to_list(), print_list() or get_list_length() functions.

1091 style debug_insert_second_last.c
    

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

1091 autotest debug_insert_second_last

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

struct node {
    struct node *next;
    int          data;
};

#define MAX_INIT_LIST_LEN 100

struct node *insert_second_last(int value, struct node *head);
struct node *create_node(int data, struct node *next);
struct node *array_to_list(int len, int array[]);
void print_list(struct node *head);
int get_list_length(struct node *head);

int main(void) {
    // Need to read in a number of ints into an array
    printf("How many numbers in initial list?: ");
    int list_size = 0;
    scanf("%d", &list_size);
    int initial_elems[MAX_INIT_LIST_LEN] = {0};
    int n_read = 0;
    while (n_read < list_size && scanf("%d", &initial_elems[n_read])) {
        n_read++;
    }

    // create linked list from first set of inputs
    struct node *head = NULL;
    if (n_read > 0) {
        // list has elements
        head = array_to_list(n_read, initial_elems);
    }

    printf("Enter the value to insert: ");
    int value;
    scanf("%d", &value);

    struct node *new_head = insert_second_last(value, head);
    print_list(new_head);

    return 0;
}

// DO NOT EDIT
// Gets the length of a linked lists
int get_list_length(struct node *head) {
    int length = 0;
    struct node *current = head;
    while (current != NULL) {
        length++;
        current = current->next;
    }
    return length;
}

// Insert a new node containing value at the second last position of the linked list.
// The head of the new list is returned.
struct node *insert_second_last(int value, struct node *head) {
    struct node *new_node = malloc(sizeof (struct node));
    new_node->data = value;
    new_node->next = NULL;

    int list_length = get_list_length(head);

    // new node is head of list
    if (head == NULL || list_length == 1) {
        new_node->next = head;
        return new_node;
    }

    struct node *p = head;
    int i = 1;
    while (p->next != NULL && i < (list_length - 1) ) {
        p = p->next;
        i++;
    }
    new_node->next = p->next;
    p->next = new_node;
    return head;
}

// DO NOT EDIT
// create linked list from array of strings
struct node *array_to_list(int len, int array[]) {
    struct node *head = NULL;
    int i = len - 1;
    while (i >= 0) {
        struct node *n = malloc(sizeof (struct node));
        n->next = head;
        n->data = array[i];
        head = n;
        i -= 1;
    }   
    return head;
}

// DO NOT EDIT
// print linked list
void print_list(struct node *head) {
    printf("[");    
    struct node *n = head;
    while (n != NULL) {
        // If you're getting an error here,
        // you have returned an invalid list
        printf("%d", n->data);
        if (n->next != NULL) {
            printf(", ");
        }
        n = n->next;
    }
    printf("]\n");
}