C语言中链表的增删改查

一个简单的C指针链表，希望对某些小伙伴有所帮助：

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct node{
  
    int id; //数据域
    char *name;
    struct node *next;//指针域
};

//类型定义
typedef struct node node_t;

//创建节点
node_t *make_node(int id, char *name);
//添加节点，从尾部添加
void llist_append_node(node_t *head, node_t *new);
//添加节点，从头部添加
void llist_append_head(node_t *head, node_t *new);
//遍历打印列表
void llist_print_each(node_t *head);
//将节点添加指定节点的后面
void llist_insert_node_after_by_id(node_t *head,node_t *new, int id);
//根据id查找节点
node_t *llist_search_node_by_id(node_t *head, int id);
//根据名字查询节点
node_t *llist_search_node_by_name(node_t *head, char *name);
//根据id找到改节点的上一个节点
node_t *llist_search_node_by_prev(node_t *head, int id);
//根据id删除节点
void llist_delete_node_by_id(node_t *head, int id);

int main(int argc, char *argv[])
{
    //创建头结点
    node_t *head = make_node(-1,"head");
    
    //创建4个结点
    node_t *n1 = make_node(1,"name1");
    node_t *n2 = make_node(2,"name2");
    node_t *n3 = make_node(3,"name3");
    node_t *n4 = make_node(4,"name4");
    
    //添加结点n1->n2->n3->n4
    llist_append_node(head,n1);
    llist_append_node(head,n2);
    llist_append_node(head,n3);
    llist_append_node(head,n4);
    //添加节点 n4->n3->n2->n1
//    llist_append_head(head,n1);
//    llist_append_head(head,n2);
//    llist_append_head(head,n3);
//    llist_append_head(head,n4);
    
    //根据id插入结点，把第5个结点插入到id为2的结点后面
    node_t *n5 = make_node(5,"name5");
    llist_insert_node_after_by_id(head,n5,2);
    
    //根据id插入结点，把第7个结点插入到id为6的结点后面
    node_t *n7 = make_node(7,"name7");
    llist_insert_node_after_by_id(head,n7,6);
    
    //根据id删除节点4
    llist_delete_node_by_id(head, 4);
    
    //打印链表内容
    llist_print_each(head);
    return 0;
}

//创建节点
node_t *make_node(int id, char *name)
{
    node_t *ret = (node_t *)malloc(sizeof(node_t));
    ret->id = id;
    ret->name = name;
    ret->next = NULL;
    return ret;
}

//添加节点，从尾部添加
void llist_append_node(node_t *head, node_t *new)
{
    node_t *cur = head;
    //找到最后的节点
    while (cur->next != NULL) {
        cur = cur->next;
    }
    cur->next = new;
}
//添加节点，从头部添加
void llist_append_head(node_t *head, node_t *new)
{
    node_t *cur = head;
    if (cur != NULL) {
        
        new->next = cur->next;
        cur->next = new;
    }
}
//根据id查找节点
node_t *llist_search_node_by_id(node_t *head, int id)
{
    node_t *cur = head;
    while (cur != NULL) {
        
        if (cur->id == id) {
            return cur;
        }
        cur = cur->next;
    }
    return NULL;
}

//将节点添加指定节点的后面
void llist_insert_node_after_by_id(node_t *head,node_t *new, int id)
{
    node_t *cur = llist_search_node_by_id(head,id);
    if (cur != NULL) {
        new->next = cur->next;
        cur->next = new;
    }else{
        llist_append_node(head,new);
    }
}

//根据名字查询节点
node_t *llist_search_node_by_name(node_t *head, char *name)
{
    node_t *cur = head;
    while (cur != NULL) {
        
        if (strcmp(cur->name,name) == 0)
        {
            return cur;
        }
        cur = cur->next;
    }
    return NULL;
}

//根据id找到改节点的上一个节点
node_t *llist_search_node_by_prev(node_t *head, int id)
{
    node_t *cur = head;
    while (cur->next != NULL) {
        
        if (cur->next->id == id) {
            printf("=====找到了\n");
            return cur;
        }
        cur = cur->next;
    }
    printf("=====没有找到了\n");
    return NULL;
}
//根据id删除节点
void llist_delete_node_by_id(node_t *head, int id)
{
    node_t *prev_node = llist_search_node_by_prev(head,id);
    if (prev_node != NULL) {
        printf("找到了前面的节点\n");
        //先保存要删除的节点
        node_t *saveNode = prev_node->next;
        prev_node->next = saveNode->next;
        saveNode->next = NULL;
        free(saveNode);
    }
}

//遍历打印列表
void llist_print_each(node_t *head)
{
    if (head == NULL) {
        return;
    }
    node_t *cur = head->next;
    while (cur != NULL) {
        printf("%p| %d | %s| %p->\n",cur,cur->id,cur->name,cur->next);
        cur = cur->next;
    }
}

最后的结果：

liaoshuhua:c语言 liaoshuhua$ gcc list.c
liaoshuhua:c语言 liaoshuhua$ ./a.out
0x7fba0fc02760| 1 | name1| 0x7fba0fc02780->
0x7fba0fc02780| 2 | name2| 0x7fba0fc027e0->
0x7fba0fc027e0| 5 | name5| 0x7fba0fc027a0->
0x7fba0fc027a0| 3 | name3| 0x7fba0fc02800->
0x7fba0fc02800| 7 | name7| 0x0->
liaoshuhua:c语言 liaoshuhua$