建立链表

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include <string.h>
#include<stdlib.h>

typedef struct _link
{
    int val;
    struct val* next;
}Link;

Link* Build()
{
    int val;
    Link* head =NULL, * tail = NULL, *cur = NULL;//头指针，尾指针，当前指针
    while (scanf("%d", &val))
    {
        cur = (Link*)malloc(sizeof(Link));//创建当前节点//为当前节点赋值，next指针指向空
        cur->val = val;
        cur->next = NULL;


        if (head == NULL)//判断是否头节点为空
        {
            head = cur;
            tail = cur;//头尾指针均指向当前节点
        }
        else
        {
            //尾节点指向当前节点，更新尾节点
            tail->next = cur;
            tail = cur;
        }
        
    }
    return head;
}