Simple C implementation of linked list with pointer to the first node and pointer the last node. Usage example included.

linkedList.c

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

typedef struct {
    int info;
} DATA;

typedef struct node {
    DATA data;
    struct node * prev;
    struct node * next;
} NODE;

typedef struct linked_list {
    NODE * first;
    NODE * last;
} linked_list;

/* The following function initializes the linked list by putting zeros into the pointers containing the first and last links of the linked list. */
void linked_list_init(linked_list * list) {
    list->first = 0;
    list->last = 0;
}

/* Return True if list is empty*/
int isEmpty(linked_list * list) {
    return (list->first == NULL);
}

/* The following function adds a new link to the end of the linked list. It allocates memory for it. The contents of the link are copied from "data". */
void linked_list_add(linked_list * list, DATA data) {
    NODE * node;

    /* calloc sets the "next" field to zero. */
    node = calloc(1, sizeof (NODE));
    if (!node) {
        printf("calloc failed.\n");
        exit(EXIT_FAILURE);
    }
    node->data = data;
    if (list->last != NULL) {
        /* Join the two final links together. */
        node->prev = list->last;
        list->last->next = node;
        list->last = node;
    } else {
        list->first = node;
        list->last = node;
    }
}

void delete_NODE(linked_list * list, NODE * node) {
    NODE * prev;
    NODE * next;
    if (isEmpty(list)) {
        return;
    }
    prev = node->prev;
    next = node->next;
    if (prev != NULL) {
        if (next != NULL) {
            /* Both the previous and next links are valid, so just bypass "link" without altering "list" at all. */
            prev->next = next;
            next->prev = prev;
        } else {
            /* Only the previous link is valid, so "prev" is now the last link in "list". */
            prev->next = 0;
            list->last = prev;
        }
    } else {
        if (next != NULL) {
            /* Only the next link is valid, not the previous one, so "next" is now the first link in "list". */
            next->prev = 0;
            list->first = next;
        } else {
            /* Neither previous nor next links are valid, so the list is now empty. */
            list->first = 0;
            list->last = 0;
        }
    }
    free(node);
}

void delete(linked_list * list, DATA data) {
    NODE * node;
    if (isEmpty(list)) {
        return;
    }
    for (node = list->first; (node != NULL) && (node->data.info != data.info); node = node->next) {
    }

    if (node == NULL) {
        printf("%d wasn't found.\nCannot Delete it.\n", data.info);
        return;
    }
    delete_NODE(list, node);
    return;
}

void traverse(linked_list * list) {
    NODE * node;
    for (node = list->first; node; node = node->next) {
        printf(" %d ", node->data.info);
    }
}

void traverse_in_reverse(linked_list * list) {
    NODE * node;
    for (node = list->last; node; node = node->prev) {
        printf(" %d ", node->data.info);
    }
}

/* Free the list's memory. */
void free_list(linked_list * list) {
    NODE * node;
    NODE * next;
    for (node = list->first; node; node = next) {
        /* Store the next value so that we don't access freed  memory. */
        next = node->next;
        free(node);
    }
    linked_list_init(list);
}

int main() {
    linked_list list;
    DATA data;
    NODE *node;
    linked_list_init(& list);
    data.info = 0;
    linked_list_add(& list, data);
    data.info = 1;
    linked_list_add(& list, data);
    data.info = 2;
    linked_list_add(& list, data);
    data.info = 3;
    linked_list_add(& list, data);

    printf("Print In Revers Order:\n\t");
    traverse_in_reverse(&list);

    printf("\nPrint In Regular Order:\n\t");
    traverse(& list);

    printf("\nDelete 1 From The List:\n\t");
    data.info = 1;
    delete(&list, data);
    traverse(& list);

    printf("\nDelete NODE From The List:\n\t");
    node = list.first->next;
    delete_NODE(&list, node);

    traverse(&list);

    free_list(&list);

    return (EXIT_SUCCESS);
}

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