数据结构(二) - 双向链表

这次我就写了最基本的创建、插入、删除、遍历这四个基本的 函数

啥也不说了 上代码

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

typedef struct linklist{
    struct linklist * lastnode;
    int data;
    struct linklist * nextnode;
} link;

bool create_link(link * head, int times);
void foreach_link(link * head); 
bool insert_element(link * head, int n, int num);
bool delete_element(link * head, int n);

int main(int argc, char *argv[])
{
    link * list = (link *)malloc(sizeof(link));
    create_link(list,5);
    printf("\n");
    foreach_link(list);
    printf("\n个数：%d\n",list->data); 
    insert_element(list, 5,13);
    printf("\n");
    foreach_link(list);
    printf("\n个数：%d\n",list->data); 
    delete_element(list,5);
    printf("\n个数：%d\n",list->data); 
    foreach_link(list); 
    delete_element(list,0);
    printf("\n个数：%d\n",list->data);
    foreach_link(list);
    return 0;
}
//建立链表 
bool create_link(link * head, int times)
{
    /*if(!head){
        printf("head has point\n");
        return false;
    }*/
    head->lastnode = NULL;
    head->nextnode = NULL;
    link * last = head;
    int temp_num;
    for(int i=0;i<times;i++){
        scanf("%d",&temp_num);
        link * temp = (link *) malloc(sizeof(link));
        temp->lastnode = last;
        temp->nextnode = NULL; 
        if(i == 0){
            head->nextnode = temp;
            temp->data = temp_num;
        }
        else{
            last->nextnode = temp;
            temp->data = temp_num;
        }
        last = temp;
    }
    head->data = times;
    return true;
}
//遍历链表
void foreach_link(link * head)
{
    link * node = head->nextnode;
    while(node)
    {
        printf("%d ",node->data);
        node = node->nextnode;
    }
}
//插入元素(之后) 下标为准 
bool insert_element(link * head, int n, int num)
{
    link * temp = (link *)malloc(sizeof(link));
    link * last = head; 
    temp->data = num;
    for(int i = 0;i < n; i++){
        last = last->nextnode;
    }
    if(n == head->data){
        last->nextnode=temp;
        temp->lastnode=last;
        head->data++;
        printf("seccess %d insert %d",n,num);
        return true;
    }
    else{
        last->nextnode->lastnode = temp;
        temp->nextnode = last->nextnode;
        temp->lastnode = last;
        last->nextnode =  temp;
        head->data++;
        printf("seccess %d insert %d",n,num);
        return true;
    }
    return false;
} 
//删除元素(之后) 下表为准 
bool delete_element(link * head, int n)
{
    link * last = head;
    link * del;
    for(int i = 0; i<n; i++){
        last = last->nextnode;
    }
    if(n == (head->data-1)){
        //free(last->nextnode);
        last->nextnode = NULL;
        head->data--;
        printf("seccess %d delete",n);
        return true;
    }
    else{
        del = last->nextnode;
        last->nextnode = del->nextnode;
        del->nextnode->lastnode = last;
        //free(del);
        head->data--; 
        printf("seccess %d delete",n);
        return true; 
    }
    return false;
}