在链接列表的“结构名称”中添加“结构名称* next”的目的是什么。 我的意思是我实际上无法处理到底发生了什么

Question

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

typedef struct employ
{
    int reg;
    int sal;
    char *name;
    struct employ *next; // I want to know the purpose of this line
}EMP;

int main(void)
{
    EMP *first,*emp1,*emp2,*emp3,*ans;
    first = (EMP *)malloc(sizeof(EMP));
    first->next = NULL;
    /////first///////
    emp1 = (EMP *)malloc(sizeof(EMP));
    if(emp1 == NULL)
    {
        perror("malloc error");
        exit(1);
    }

    emp1->reg = 100;
    emp1->sal = 30000;
    emp1->name = "james";
    emp1->next = first;
    first = emp1;

    /* I havent completed the program bcoz its not necessary here */

Answer 1

In a linked list, each node contains a pointer to the next node.

struct employ *next;

is used to achieve that effect

+---------+        +---------+
|  Node1  |------->|  Node2  |----> ...  
+---------+        +---------+

if you are in node1, next is a pointer to node2, that way you can accesss next element from the current element

Answer 2

A linked list is a data structure consisting of a group of nodes which together represent a sequence. Here the reg , sal and *name represent your data structure and *next will hold the link to next element in the list.

Consider the following data structure

struct sample {
 int number;
 struct sample *next;
};

The pictorial representation for this structure would be

The above example has 3 elements, every element is an individual structure variable. In the above example the variable 1 has members number and *next . Here, the number contains 12 and the *next contains the address of the structure variable holding the data 99 . Since the type of the variable holding the data 99 is of type struct sample that is why we take *next type as struct sample type.