Double Linked List

//Double Linked List
#include<stdio.h>
#include<stdlib.h>

 typedef struct _node
{
     int data;
     struct _node* back;
     struct _node* next;
}node;
node *head, *tail;

 void print_all(void);
void init_link(void);
void insert_link(int x);
node* find_node(int x);
void insert_before(int x, node* y);
void del_node(node* x);
void all_del_node(void);

 void main()
{
    init_link();
    insert_link(10);
    insert_link(5);
    insert_link(8);
    insert_link(3);
    insert_link(1);
    insert_link(7);
    insert_link(8);

    printf("Inital Linked list is ");
    print_all();

     printf("Finding 4 is %s\n", find_node(4) != tail ? "successful" : "unsuccessful");
    printf("Finding 5 is %s\n", find_node(5) != tail  ? "successful" : "unsuccessful");

     puts("Inserting 7 before 5");
    insert_before(7, find_node(5));
    print_all();

     puts("Deleting 3");
    del_node(find_node(3));
    print_all();

     puts("Inserting node 2 before 10");
    insert_before(2, find_node(10));
    print_all();

     puts("Deleting 2");
    del_node(find_node(2));
    print_all();

     puts("Deleting 1");
    del_node(find_node(1));
    print_all();

     puts("Insering node 15");
    insert_before(15, head->next);
    print_all();

     puts("Deleting all node");
    all_del_node();
    print_all();
}

 //전체 노드 삭제

void all_del_node(void)
{
    node* temp;
    temp = head->next;
    while(temp != tail)
    {
        temp = temp->next;
        free(temp->back);
    }

    //노드 초기화
    head->next = tail;
    tail->back = head;
}

 

//노드를 입력받아 삭제

void del_node(node* x)
{
    if(x != tail)
    {
        x->back->next = x->next;
        x->next->back = x->back;
        free(x);
    }
    else
        puts("!!!!!!!!!!!!!!!!! Not Node !!!!!!!!!!!!!!!!!");
}

 

//찾은 노드 이전에 삽입

void insert_before(int x, node* y)
{
    node* temp = (node*)malloc(sizeof(node));

    temp->data = x;
    y->back->next = temp;
    temp->back = y->back;
    y->back = temp;
    temp->next = y;
}

 

//노드 찾기
node* find_node(int x)
{
    node* temp;
    temp = head->next;
    while(temp->data != x && temp != tail)
        temp = temp->next;
    return temp;
}

 

//노드값 화면에 출력

void print_all(void)
{
    node* temp;
    temp = head->next;
    while(temp != tail)
    {
        printf("%5d",temp->data);
        temp = temp->next;
    }
    printf("\n");
}

 

//노드 초기화

void init_link(void)
{
    head = (node*)malloc(sizeof(node));
    tail = (node*)malloc(sizeof(node));
    head->next = tail;
    head->back = head;
    tail->next = tail;
    tail->back = head;
}

 

//노드 입력 받기
void insert_link(int x)
{
    node *a;
    node* temp = (node*)malloc(sizeof(node));
   
    a = head->next;
    while(a->data <= x && a != tail)
     a = a->next;

    temp->data = x;
    a->back->next = temp;
    temp->back = a->back;
    temp->next = a;
    a->back = temp;
}