C로 이중 연결 리스트 구현하기

C언어 코딩도장 Unit 74. 연결 리스트 구현하기 코드를 참고해서 만들었다.

DoublyLinkedList.c

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

struct Node {
    int data;
    struct Node *next;
    struct Node *prev;
};

void addFirst(struct Node *target, int data){
    if (target == NULL){
        return;
    }
    
    struct Node *newNode = malloc(sizeof(struct Node));
    newNode->next = target->next; 
    newNode->prev = target;
    newNode->data = data;

    target->next = newNode;
    if (newNode->next != NULL){
        newNode->next->prev = newNode;
    }
}

void removeFirst(struct Node *target){
    if (target == NULL){
        return;
    }
    
    struct Node *removeNode = target->next;
    target->next = removeNode->next;
    removeNode->prev = target;
    free(removeNode);
}

int main(){
    struct Node *head = malloc(sizeof(struct Node));
    head->next = NULL;

    addFirst(head, 10);
    addFirst(head, 20);
    addFirst(head, 30);
    addFirst(head, 40);

    struct Node *cur = head->next;
    while (cur != NULL){ 
        printf("%d\n", cur->data);
        cur = cur->next;
    }

    cur = head->next;
    while (cur != NULL){
        struct Node *next = cur->next;
        free(cur);
        cur = next;
    }

    free(head);
    return 0;
}