Name	Name	Last commit message	Last commit date
parent directory ..
.gitignore	.gitignore
0-print_dlistint.c	0-print_dlistint.c
1-dlistint_len.c	1-dlistint_len.c
100-password	100-password
102-result	102-result
103-keygen.c	103-keygen.c
2-add_dnodeint.c	2-add_dnodeint.c
3-add_dnodeint_end.c	3-add_dnodeint_end.c
4-free_dlistint.c	4-free_dlistint.c
5-get_dnodeint.c	5-get_dnodeint.c
6-sum_dlistint.c	6-sum_dlistint.c
7-insert_dnodeint.c	7-insert_dnodeint.c
8-delete_dnodeint.c	8-delete_dnodeint.c
README.md	README.md
lists.h	lists.h

0x17. C - Doubly linked lists

By Julien Barbier

In a nutshell...

Auto QA review: 0.0/98 mandatory & 0.0/16 optional
Altogether: 0.0%
- Mandatory: 0.0%
- Optional: 0.0%
- Calculation: 0.0% + (0.0% * 0.0%) == 0.0%

Resources

Read or watch:

What is a Doubly Linked List

Learning Objectives

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

General

What is a doubly linked list
How to use doubly linked lists
Start to look for the right source of information without too much help

Requirements

General

Allowed editors: vi, vim, emacs
All your files will be interpreted/compiled on Ubuntu 20.04 LTS using python3 (version 3.8.5)
All your files should end with a new line
A README.md file, at the root of the folder of the project is mandatory
Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
You are not allowed to use global variables
No more than 5 functions per file
The only C standard library functions allowed are malloc, free, printf and exit
In the following examples, the main.c files are shown as examples. You can use them to test your functions, but you don't have to push them to your repo (if you do we won't take them into account). We will use our own main.c files at compilation. Our main.c files might be different from the one shown in the examples
The prototypes of all your functions should be included in your header file called lists.h
Don't forget to push your header file
All your header files should be include guarded

More Info

Please use this data structure for this project:

/**
 * struct dlistint_s - doubly linked list
 * @n: integer
 * @prev: points to the previous node
 * @next: points to the next node
 *
 * Description: doubly linked list node structure
 *
 */
typedef struct dlistint_s
{
    int n;
    struct dlistint_s *prev;
    struct dlistint_s *next;
} dlistint_t;

Quiz questions

Show

Tasks

0. Print list

mandatory

Score: 0.00% (Checks completed: 0.00%)

Write a function that prints all the elements of a dlistint_t list.

Prototype: size_t print_dlistint(const dlistint_t *h);
Return: the number of nodes
Format: see example

julien@ubuntu:~/0x17. Doubly linked lists$ cat 0-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;
    dlistint_t *new;
    dlistint_t hello = {8, NULL, NULL};
    size_t n;

    head = &hello;
    new = malloc(sizeof(dlistint_t));
    if (new == NULL)
    {
        dprintf(2, "Error: Can't malloc\n");
        return (EXIT_FAILURE);
    }
    new->n = 9;
    head->prev = new;
    new->next = head;
    new->prev = NULL;
    head = new;
    n = print_dlistint(head);
    printf("-> %lu elements\n", n);
    free(new);
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 0-main.c 0-print_dlistint.c -o a
julien@ubuntu:~/0x17. Doubly linked lists$ ./a
9
8
-> 2 elements
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

GitHub repository: alx-low_level_programming
Directory: 0x17-doubly_linked_lists
File: 0-print_dlistint.c

1. List length

mandatory

Score: 0.00% (Checks completed: 0.00%)

Write a function that returns the number of elements in a linked dlistint_t list.

Prototype: size_t dlistint_len(const dlistint_t *h);

julien@ubuntu:~/0x17. Doubly linked lists$ cat 1-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;
    dlistint_t *new;
    dlistint_t hello = {8, NULL, NULL};
    size_t n;

    head = &hello;
    new = malloc(sizeof(dlistint_t));
    if (new == NULL)
    {
        dprintf(2, "Error: Can't malloc\n");
        return (EXIT_FAILURE);
    }
    new->n = 9;
    head->prev = new;
    new->next = head;
    new->prev = NULL;
    head = new;
    n = dlistint_len(head);
    printf("-> %lu elements\n", n);
    free(new);
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 1-main.c 1-dlistint_len.c -o b
julien@ubuntu:~/0x17. Doubly linked lists$ ./b
-> 2 elements
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

GitHub repository: alx-low_level_programming
Directory: 0x17-doubly_linked_lists
File: 1-dlistint_len.c

2. Add node

mandatory

Score: 0.00% (Checks completed: 0.00%)

Write a function that adds a new node at the beginning of a dlistint_t list.

Prototype: dlistint_t *add_dnodeint(dlistint_t **head, const int n);
Return: the address of the new element, or NULL if it failed

julien@ubuntu:~/0x17. Doubly linked lists$ cat 2-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint(&head, 0);
    add_dnodeint(&head, 1);
    add_dnodeint(&head, 2);
    add_dnodeint(&head, 3);
    add_dnodeint(&head, 4);
    add_dnodeint(&head, 98);
    add_dnodeint(&head, 402);
    add_dnodeint(&head, 1024);
    print_dlistint(head);
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 2-main.c 2-add_dnodeint.c 0-print_dlistint.c -o c
julien@ubuntu:~/0x17. Doubly linked lists$ ./c
1024
402
98
4
3
2
1
0
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

GitHub repository: alx-low_level_programming
Directory: 0x17-doubly_linked_lists
File: 2-add_dnodeint.c

3. Add node at the end

mandatory

Score: 0.00% (Checks completed: 0.00%)

Write a function that adds a new node at the end of a dlistint_t list.

Prototype: dlistint_t *add_dnodeint_end(dlistint_t **head, const int n);
Return: the address of the new element, or NULL if it failed

julien@ubuntu:~/0x17. Doubly linked lists$ cat 3-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 3-main.c 3-add_dnodeint_end.c 0-print_dlistint.c -o d
julien@ubuntu:~/0x17. Doubly linked lists$ ./d
0
1
2
3
4
98
402
1024
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

GitHub repository: alx-low_level_programming
Directory: 0x17-doubly_linked_lists
File: 3-add_dnodeint_end.c

4. Free list

mandatory

Score: 0.00% (Checks completed: 0.00%)

Write a function that frees a dlistint_t list.

Prototype: void free_dlistint(dlistint_t *head);

julien@ubuntu:~/0x17. Doubly linked lists$ cat 4-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    free_dlistint(head);
    head = NULL;
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 4-main.c 3-add_dnodeint_end.c 0-print_dlistint.c 4-free_dlistint.c -o e
julien@ubuntu:~/0x17. Doubly linked lists$ valgrind ./e
==4197== Memcheck, a memory error detector
==4197== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==4197== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==4197== Command: ./e
==4197==
0
1
2
3
4
98
402
1024
==4197==
==4197== HEAP SUMMARY:
==4197==     in use at exit: 0 bytes in 0 blocks
==4197==   total heap usage: 9 allocs, 9 frees, 1,216 bytes allocated
==4197==
==4197== All heap blocks were freed -- no leaks are possible
==4197==
==4197== For counts of detected and suppressed errors, rerun with: -v
==4197== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

GitHub repository: alx-low_level_programming
Directory: 0x17-doubly_linked_lists
File: 4-free_dlistint.c

5. Get node at index

mandatory

Score: 0.00% (Checks completed: 0.00%)

Write a function that returns the nth node of a dlistint_t linked list.

Prototype: dlistint_t *get_dnodeint_at_index(dlistint_t *head, unsigned int index);
where index is the index of the node, starting from 0
if the node does not exist, return NULL

julien@ubuntu:~/0x17. Doubly linked lists$ cat 5-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;
    dlistint_t *node;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    node = get_dnodeint_at_index(head, 5);
    printf("%d\n", node->n);
    free_dlistint(head);
    head = NULL;
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 5-main.c 3-add_dnodeint_end.c 0-print_dlistint.c 4-free_dlistint.c 5-get_dnodeint.c -o h
julien@ubuntu:~/0x17. Doubly linked lists$ ./h
0
1
2
3
4
98
402
1024
98
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

GitHub repository: alx-low_level_programming
Directory: 0x17-doubly_linked_lists
File: 5-get_dnodeint.c

6. Sum list

mandatory

Score: 0.00% (Checks completed: 0.00%)

Write a function that returns the sum of all the data (n) of a dlistint_t linked list.

Prototype: int sum_dlistint(dlistint_t *head);
if the list is empty, return 0

julien@ubuntu:~/0x17. Doubly linked lists$ cat 6-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;
    int sum;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    sum = sum_dlistint(head);
    printf("sum = %d\n", sum);
    free_dlistint(head);
    head = NULL;
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra 6-main.c -std=gnu89 3-add_dnodeint_end.c 4-free_dlistint.c 6-sum_dlistint.c -o i
julien@ubuntu:~/0x17. Doubly linked lists$ ./i
sum = 1534
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

GitHub repository: alx-low_level_programming
Directory: 0x17-doubly_linked_lists
File: 6-sum_dlistint.c

7. Insert at index

mandatory

Score: 0.00% (Checks completed: 0.00%)

Write a function that inserts a new node at a given position.

Prototype: dlistint_t *insert_dnodeint_at_index(dlistint_t **h, unsigned int idx, int n);
where idx is the index of the list where the new node should be added. Index starts at 0
Returns: the address of the new node, or NULL if it failed
if it is not possible to add the new node at index idx, do not add the new node and return NULL

Your files 2-add_dnodeint.c and 3-add_dnodeint_end.c will be compiled during the correction

julien@ubuntu:~/0x17. Doubly linked lists$ cat 7-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    printf("-----------------\n");
    insert_dnodeint_at_index(&head, 5, 4096);
    print_dlistint(head);
    free_dlistint(head);
    head = NULL;
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 7-main.c 2-add_dnodeint.c 3-add_dnodeint_end.c 0-print_dlistint.c 4-free_dlistint.c 7-insert_dnodeint.c -o j
julien@ubuntu:~/0x17. Doubly linked lists$ ./j
0
1
2
3
4
98
402
1024
-----------------
0
1
2
3
4
4096
98
402
1024
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

GitHub repository: alx-low_level_programming
Directory: 0x17-doubly_linked_lists
File: 7-insert_dnodeint.c, 2-add_dnodeint.c, 3-add_dnodeint_end.c

8. Delete at index

mandatory

Score: 0.00% (Checks completed: 0.00%)

Write a function that deletes the node at index index of a dlistint_t linked list.

Prototype: int delete_dnodeint_at_index(dlistint_t **head, unsigned int index);
where index is the index of the node that should be deleted. Index starts at 0
Returns: 1 if it succeeded, -1 if it failed

julien@ubuntu:~/0x17. Doubly linked lists$ cat 8-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 5);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    return (0);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 8-main.c 3-add_dnodeint_end.c 0-print_dlistint.c 4-free_dlistint.c 8-delete_dnodeint.c -o k
julien@ubuntu:~/0x17. Doubly linked lists$ ./k
0
1
2
3
4
98
402
1024
-----------------
0
1
2
3
4
402
1024
-----------------
1
2
3
4
402
1024
-----------------
2
3
4
402
1024
-----------------
3
4
402
1024
-----------------
4
402
1024
-----------------
402
1024
-----------------
1024
-----------------0x17. C - Doubly linked lists

    By Julien Barbier
    Weight: 1
    Ongoing second chance project - started 11-25-2021, must end by 11-27-2021 (in about 10 hours) - you're done with 0% of tasks.
    QA review fully automated.
    In a nutshell…
        Auto QA review: 0.0/98 mandatory & 0.0/16 optional
        Altogether:  0.0%
            Mandatory: 0.0%
            Optional: 0.0%
            Calculation:  0.0% + (0.0% * 0.0%)  == 0.0%

Resources

Read or watch:

    What is a Doubly Linked List

Learning Objectives

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:
General

    What is a doubly linked list
    How to use doubly linked lists
    Start to look for the right source of information without too much help

Requirements
General

    Allowed editors: vi, vim, emacs
    All your files will be interpreted/compiled on Ubuntu 20.04 LTS using python3 (version 3.8.5)
    All your files should end with a new line
    A README.md file, at the root of the folder of the project is mandatory
    Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
    You are not allowed to use global variables
    No more than 5 functions per file
    The only C standard library functions allowed are malloc, free, printf and exit
    In the following examples, the main.c files are shown as examples. You can use them to test your functions, but you don’t have to push them to your repo (if you do we won’t take them into account). We will use our own main.c files at compilation. Our main.c files might be different from the one shown in the examples
    The prototypes of all your functions should be included in your header file called lists.h
    Don’t forget to push your header file
    All your header files should be include guarded

More Info

Please use this data structure for this project:

/**
 * struct dlistint_s - doubly linked list
 * @n: integer
 * @prev: points to the previous node
 * @next: points to the next node
 *
 * Description: doubly linked list node structure
 * 
 */
typedef struct dlistint_s
{
    int n;
    struct dlistint_s *prev;
    struct dlistint_s *next;
} dlistint_t;

Quiz questions

Show
Tasks
0. Print list
mandatory
Score: 0.00% (Checks completed: 0.00%)

Write a function that prints all the elements of a dlistint_t list.

    Prototype: size_t print_dlistint(const dlistint_t *h);
    Return: the number of nodes
    Format: see example

julien@ubuntu:~/0x17. Doubly linked lists$ cat 0-main.c 
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;
    dlistint_t *new;
    dlistint_t hello = {8, NULL, NULL};
    size_t n;

    head = &hello;
    new = malloc(sizeof(dlistint_t));
    if (new == NULL)
    {
        dprintf(2, "Error: Can't malloc\n");
        return (EXIT_FAILURE);
    }
    new->n = 9;
    head->prev = new;
    new->next = head;
    new->prev = NULL;
    head = new;
    n = print_dlistint(head);
    printf("-> %lu elements\n", n);
    free(new);
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 0-main.c 0-print_dlistint.c -o a
julien@ubuntu:~/0x17. Doubly linked lists$ ./a 
9
8
-> 2 elements
julien@ubuntu:~/0x17. Doubly linked lists$ 

Repo:

    GitHub repository: alx-low_level_programming
    Directory: 0x17-doubly_linked_lists
    File: 0-print_dlistint.c

1. List length
mandatory
Score: 0.00% (Checks completed: 0.00%)

Write a function that returns the number of elements in a linked dlistint_t list.

    Prototype: size_t dlistint_len(const dlistint_t *h);

julien@ubuntu:~/0x17. Doubly linked lists$ cat 1-main.c 
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;
    dlistint_t *new;
    dlistint_t hello = {8, NULL, NULL};
    size_t n;

    head = &hello;
    new = malloc(sizeof(dlistint_t));
    if (new == NULL)
    {
        dprintf(2, "Error: Can't malloc\n");
        return (EXIT_FAILURE);
    }
    new->n = 9;
    head->prev = new;
    new->next = head;
    new->prev = NULL;
    head = new;
    n = dlistint_len(head);
    printf("-> %lu elements\n", n);
    free(new);
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 1-main.c 1-dlistint_len.c -o b
julien@ubuntu:~/0x17. Doubly linked lists$ ./b 
-> 2 elements
julien@ubuntu:~/0x17. Doubly linked lists$ 

Repo:

    GitHub repository: alx-low_level_programming
    Directory: 0x17-doubly_linked_lists
    File: 1-dlistint_len.c

2. Add node
mandatory
Score: 0.00% (Checks completed: 0.00%)

Write a function that adds a new node at the beginning of a dlistint_t list.

    Prototype: dlistint_t *add_dnodeint(dlistint_t **head, const int n);
    Return: the address of the new element, or NULL if it failed

julien@ubuntu:~/0x17. Doubly linked lists$ cat 2-main.c 
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint(&head, 0);
    add_dnodeint(&head, 1);
    add_dnodeint(&head, 2);
    add_dnodeint(&head, 3);
    add_dnodeint(&head, 4);
    add_dnodeint(&head, 98);
    add_dnodeint(&head, 402);
    add_dnodeint(&head, 1024);
    print_dlistint(head);
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 2-main.c 2-add_dnodeint.c 0-print_dlistint.c -o c
julien@ubuntu:~/0x17. Doubly linked lists$ ./c 
1024
402
98
4
3
2
1
0
julien@ubuntu:~/0x17. Doubly linked lists$ 

Repo:

    GitHub repository: alx-low_level_programming
    Directory: 0x17-doubly_linked_lists
    File: 2-add_dnodeint.c

3. Add node at the end
mandatory
Score: 0.00% (Checks completed: 0.00%)

Write a function that adds a new node at the end of a dlistint_t list.

    Prototype: dlistint_t *add_dnodeint_end(dlistint_t **head, const int n);
    Return: the address of the new element, or NULL if it failed

julien@ubuntu:~/0x17. Doubly linked lists$ cat 3-main.c 
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 3-main.c 3-add_dnodeint_end.c 0-print_dlistint.c -o d
julien@ubuntu:~/0x17. Doubly linked lists$ ./d 
0
1
2
3
4
98
402
1024
julien@ubuntu:~/0x17. Doubly linked lists$ 

Repo:

    GitHub repository: alx-low_level_programming
    Directory: 0x17-doubly_linked_lists
    File: 3-add_dnodeint_end.c

4. Free list
mandatory
Score: 0.00% (Checks completed: 0.00%)

Write a function that frees a dlistint_t list.

    Prototype: void free_dlistint(dlistint_t *head);

julien@ubuntu:~/0x17. Doubly linked lists$ cat 4-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    free_dlistint(head);
    head = NULL;
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 4-main.c 3-add_dnodeint_end.c 0-print_dlistint.c 4-free_dlistint.c -o e
julien@ubuntu:~/0x17. Doubly linked lists$ valgrind ./e 
==4197== Memcheck, a memory error detector
==4197== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==4197== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==4197== Command: ./e
==4197== 
0
1
2
3
4
98
402
1024
==4197== 
==4197== HEAP SUMMARY:
==4197==     in use at exit: 0 bytes in 0 blocks
==4197==   total heap usage: 9 allocs, 9 frees, 1,216 bytes allocated
==4197== 
==4197== All heap blocks were freed -- no leaks are possible
==4197== 
==4197== For counts of detected and suppressed errors, rerun with: -v
==4197== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
julien@ubuntu:~/0x17. Doubly linked lists$ 

Repo:

    GitHub repository: alx-low_level_programming
    Directory: 0x17-doubly_linked_lists
    File: 4-free_dlistint.c

5. Get node at index
mandatory
Score: 0.00% (Checks completed: 0.00%)

Write a function that returns the nth node of a dlistint_t linked list.

    Prototype: dlistint_t *get_dnodeint_at_index(dlistint_t *head, unsigned int index);
    where index is the index of the node, starting from 0
    if the node does not exist, return NULL

julien@ubuntu:~/0x17. Doubly linked lists$ cat 5-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;
    dlistint_t *node;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    node = get_dnodeint_at_index(head, 5);
    printf("%d\n", node->n);
    free_dlistint(head);
    head = NULL;
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 5-main.c 3-add_dnodeint_end.c 0-print_dlistint.c 4-free_dlistint.c 5-get_dnodeint.c -o h
julien@ubuntu:~/0x17. Doubly linked lists$ ./h
0
1
2
3
4
98
402
1024
98
julien@ubuntu:~/0x17. Doubly linked lists$ 

Repo:

    GitHub repository: alx-low_level_programming
    Directory: 0x17-doubly_linked_lists
    File: 5-get_dnodeint.c

6. Sum list
mandatory
Score: 0.00% (Checks completed: 0.00%)

Write a function that returns the sum of all the data (n) of a dlistint_t linked list.

    Prototype: int sum_dlistint(dlistint_t *head);
    if the list is empty, return 0

julien@ubuntu:~/0x17. Doubly linked lists$ cat 6-main.c 
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;
    int sum;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    sum = sum_dlistint(head);
    printf("sum = %d\n", sum);
    free_dlistint(head);
    head = NULL;
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra 6-main.c -std=gnu89 3-add_dnodeint_end.c 4-free_dlistint.c 6-sum_dlistint.c -o i
julien@ubuntu:~/0x17. Doubly linked lists$ ./i 
sum = 1534
julien@ubuntu:~/0x17. Doubly linked lists$ 

Repo:

    GitHub repository: alx-low_level_programming
    Directory: 0x17-doubly_linked_lists
    File: 6-sum_dlistint.c

7. Insert at index
mandatory
Score: 0.00% (Checks completed: 0.00%)

Write a function that inserts a new node at a given position.

    Prototype: dlistint_t *insert_dnodeint_at_index(dlistint_t **h, unsigned int idx, int n);
    where idx is the index of the list where the new node should be added. Index starts at 0
    Returns: the address of the new node, or NULL if it failed
    if it is not possible to add the new node at index idx, do not add the new node and return NULL

Your files 2-add_dnodeint.c and 3-add_dnodeint_end.c will be compiled during the correction

julien@ubuntu:~/0x17. Doubly linked lists$ cat 7-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    printf("-----------------\n");
    insert_dnodeint_at_index(&head, 5, 4096);
    print_dlistint(head);
    free_dlistint(head);
    head = NULL;
    return (EXIT_SUCCESS);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 7-main.c 2-add_dnodeint.c 3-add_dnodeint_end.c 0-print_dlistint.c 4-free_dlistint.c 7-insert_dnodeint.c -o j
julien@ubuntu:~/0x17. Doubly linked lists$ ./j 
0
1
2
3
4
98
402
1024
-----------------
0
1
2
3
4
4096
98
402
1024
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

    GitHub repository: alx-low_level_programming
    Directory: 0x17-doubly_linked_lists
    File: 7-insert_dnodeint.c, 2-add_dnodeint.c, 3-add_dnodeint_end.c

8. Delete at index
mandatory
Score: 0.00% (Checks completed: 0.00%)

Write a function that deletes the node at index index of a dlistint_t linked list.

    Prototype: int delete_dnodeint_at_index(dlistint_t **head, unsigned int index);
    where index is the index of the node that should be deleted. Index starts at 0
    Returns: 1 if it succeeded, -1 if it failed

julien@ubuntu:~/0x17. Doubly linked lists$ cat 8-main.c
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lists.h"

/**
 * main - check the code
 *
 * Return: Always EXIT_SUCCESS.
 */
int main(void)
{
    dlistint_t *head;

    head = NULL;
    add_dnodeint_end(&head, 0);
    add_dnodeint_end(&head, 1);
    add_dnodeint_end(&head, 2);
    add_dnodeint_end(&head, 3);
    add_dnodeint_end(&head, 4);
    add_dnodeint_end(&head, 98);
    add_dnodeint_end(&head, 402);
    add_dnodeint_end(&head, 1024);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 5);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    printf("-----------------\n");
    delete_dnodeint_at_index(&head, 0);
    print_dlistint(head);
    return (0);
}
julien@ubuntu:~/0x17. Doubly linked lists$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 8-main.c 3-add_dnodeint_end.c 0-print_dlistint.c 4-free_dlistint.c 8-delete_dnodeint.c -o k
julien@ubuntu:~/0x17. Doubly linked lists$ ./k
0
1
2
3
4
98
402
1024
-----------------
0
1
2
3
4
402
1024
-----------------
1
2
3
4
402
1024
-----------------
2
3
4
402
1024
-----------------
3
4
402
1024
-----------------
4
402
1024
-----------------
402
1024
-----------------
1024
-----------------
-----------------
-----------------
-----------------
-----------------
-----------------
-----------------
-----------------
-----------------
-----------------
julien@ubuntu:~/0x17. Doubly linked lists$ 

Repo:

    GitHub repository: alx-low_level_programming
    Directory: 0x17-doubly_linked_lists
    File: 8-delete_dnodeint.c


-----------------
-----------------
-----------------
-----------------
-----------------
-----------------
-----------------
-----------------
-----------------
julien@ubuntu:~/0x17. Doubly linked lists$

Repo:

GitHub repository: alx-low_level_programming
Directory: 0x17-doubly_linked_lists
File: 8-delete_dnodeint.c

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README.md

0x17. C - Doubly linked lists

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0. Print list

1. List length

2. Add node

3. Add node at the end

4. Free list

5. Get node at index

6. Sum list

7. Insert at index

8. Delete at index

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README.md

0x17. C - Doubly linked lists

In a nutshell...

Resources

Learning Objectives

General

Requirements

General

More Info

Quiz questions

Tasks

0. Print list

1. List length

2. Add node

3. Add node at the end

4. Free list

5. Get node at index

6. Sum list

7. Insert at index

8. Delete at index