无头链表

头文件定义

#include "head.h"


typedef struct  Student{
    int age;
    struct Student *next;
} Stu;

//初始化链表
int init_link_list(Stu **head);

//创建节点
int create_node(int age, Stu **node);

//释放节点
int free_node(Stu **node);

//在表尾部插入
int insert_node_to_foot(Stu *node, Stu **head);

//在表头部插入
int insert_node_to_head(Stu *node, Stu **head);

//在local位置插入node节点
int insert_node_to_any_location(Stu *node, Stu **head, int local);

//找到age对应的node
Stu * find_node(int age, Stu *head);

//删除对应节点
int delete_node(Stu *node,Stu **head);

//打印link
void print_link(Stu *head);

//销毁链表
int free_link(Stu **head);

//获取链表长度
int get_link_length(Stu *head);

#endif /* Link_list_h */

链表实现

//初始化链表
int init_link_list(Stu **head){
    
    if (head != NULL) {
        
        *head = NULL;
    }else{
        return  -1;
    }
    
    return 0;
}

//创建节点
int create_node(int age, Stu **node){

    if (node == NULL) {
        
        return -1;
    }
    
    Stu *node_in = calloc(1, sizeof(Stu));
    
    if (node == NULL) {
        
        return -1;
    }
    
    node_in->age = age;
    node_in->next = NULL;
    
    *node = node_in;
    
    return 0;
}

//释放节点
int free_node(Stu **node){
   
    if (node == NULL || *node == NULL) {
        
        return -1;
    }
    
    free(*node);
    
    *node = NULL;
    return  0;
}

//在表尾部插入
int insert_node_to_foot(Stu *node, Stu **head){

    if (node == NULL || head== NULL ) {
        
        return  -1;
    }
    
    if (*head == NULL) {
        
        *head = node;
        
        return 0;
    }
    
    Stu *p = *head;
    while (p->next) {
        
        p = p->next;
    }
    
    p->next = node;
    
    return 0;
}

//在表头部插入
int insert_node_to_head(Stu *node, Stu **head){

    if (node == NULL || head == NULL) {
        
        return -1;
    }

    Stu *p = *head;
    *head = node;
    node->next = p;
    
    return 0;
}

//任何位置插入
int insert_node_to_any_location(Stu *node, Stu **head, int local){

    
    if (node == NULL || head== NULL ) {
        return -1;
    }
    
    if ( local < 1 || local > get_link_length(*head)) {
        
        fprintf(stderr, "local参数错误");
        return  -1;
    }
    
    if (local == 1) {
        
        Stu *p = (*head);
        *head = node;
        node->next = p;
        
        return  0;
    }
    
    Stu *p = *head;
    
    Stu *q = p;
    int index = 0;
    while (p) {
        
        index++;
        if (index  == local) {
            break;
        }
        
        q = p;
        p = p->next;
    }
    
    if (p) {
        
        Stu *temp = q->next;
        q->next = node;
        node->next = temp;
    }
    return 0;
}

int get_link_length(Stu *head){

    int length = 0;
    
    Stu *p = head;
    
    while (p) {
        
        length++;
        p = p->next;
    }
    
    return length;
}

//找到age对应的node
Stu * find_node(int age, Stu *head){

    if (head == NULL) {
        
        return NULL;
    }
    
    
    Stu *p = head;
    while (p != NULL) {
        
        if (age == p->age) {
            
            return p;
        }
        p = p->next;
    }
    
    return NULL;
}

int delete_node(Stu *node,Stu **head){
   
    if (node == NULL || head == NULL || *head == NULL) {
        
        return -1;
    }
    
    
    //这里要改变头指针，要单独判断
    if (node == *head) {
        
        *head = (*head)->next;
        return 0;
    }
    
    Stu *head_in = *head;
    Stu *p = *head;
    
    while (head_in) {
        
        if (head_in == node) {
            
            p->next = head_in->next;
            
            free_node(&head_in);
            return 0;
        }
        
        p = head_in;
        head_in = head_in->next;
    }
    
    return  0;
}

//打印link
void print_link(Stu *head){
    
    Stu *p = head;
   
    while (p) {
        
        printf("%d\n", p->age);
        p = p->next;
    }
}

//销毁链表
int free_link(Stu **head){

    if (head == NULL || *head == NULL) {
        return -1;
    }
    
    Stu *p = *head;
    Stu *q = NULL;
    while (p) {
        
        q = p;
        p = p->next;
        
        free_node(&q);
    }
   
    *head = NULL;
    return 0;
}

测试

void link_list_test(){
   
    Stu *head ;
    
    init_link_list(&head);
    
    int age = 0;
    while (1) {
        
        printf("请输入年龄:");
        scanf("%d", &age);
        if (age == -1) {
            break;
        }
        Stu *node = NULL;
        if (create_node(age, &node) == 0) {
            
            insert_node_to_head(node, &head);
//            insert_node_to_foot(node, &head);
        }
        
    }

    print_link(head);
//    while (1) {
//        
//        printf("请输入要删除的节点:");
//        scanf("%d", &age);
//        if (age <= 0) {
//            
//            break;
//        }
//        Stu *find = find_node(age, head);
//        if (find !=NULL) {
//            
//            delete_node(find, &head);
//        }
//        
//        
//        print_link(head);
//
//    }
    
    while (1) {
        
          int age, local;
          printf("请输入要插入的节点，以及插入的位置:");
        
        scanf("%d,%d",&age,&local);
        
        if (age <= 0) {
            
            break;
        }
        Stu *node = NULL;
        create_node(age, &node);
        
        insert_node_to_any_location(node, &head, local);
        
        print_link(head);
    }
    
    free_link(&head);
    
}