How to create a linked list using a struct inside the node element - linked-list

Question

I tried to create a linked list, using a node that had a structure inside it to hold the info data. Whenever I try to do that , I have a compiled error telling me that I am using an "incomplete" type, and I am not sure why.
The exact error I have is the following:
main.c: In function ‘createList’:
main.c:53:46: error: invalid application of ‘sizeof’ to incomplete type ‘typeNode’ {aka ‘struct StructInfoNodo’}
53 | if ((new_node = (typeNode *) malloc (sizeof (typeNode))) == NULL)
| ^~~~~~~~
main.c:59:9: error: dereferencing pointer to incomplete type ‘typeNode’ {aka ‘struct StructInfoNodo’}
59 | new_node->info.idCell=nodeinfo.idCell;
| ^~
main2.c:67:5: warning: statement with no effect [-Wunused-value]
67 | list->num_nodes;
| ~~~~^~~~~~~~~~~
In my code, I have a createList funtion, which tries to create the first node of the list, using some sample data. However, I am unable to the initial malloc, seems it does not recognize the new type that was defined (typeNet) to hold the info inside a structure.
I was using for that the following instruct: new_node = (typeNode *) malloc (sizeof (typeNode))
and after that, I was trying to do new_node->info.idCell=nodeinfo.idCell;
That lines result in the errors shown above.
Any idea on how I can solve it, and be able to write info on the node?
Please find below the complete code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAXCHAR 80
struct structInfoNet
{
int idCell;
char MacAddress[MAXCHAR];
char Essid[MAXCHAR];
char Mode[MAXCHAR];
int Channel;
};
typedef struct structInfoNet typeNet;
struct structInfoNode
{
typeNet info;
struct structInfoNode* nextNode;
};
typedef struct StructInfoNodo typeNode;
/* Struct to store pointers to firs & last element linked list */
struct structInfoLista {
typeNode *firstNode;
typeNode *lastNode;
int num_nodes;
};
typedef struct structInfoLista typeInfoList;
/* Initialitate frist & last elements linked list */
void initLinkedList (typeInfoList *list){
list->firstNode = NULL;
list->lastNode = NULL;
list->num_nodes= 0;
}
/* Insert First Element on the List (CreateList) */
int createList (typeInfoList * list, typeNet nodeinfo) {
typeNode *new_node;
if ((new_node = (typeNode *) malloc (sizeof (typeNode))) == NULL)
{
printf ("Error. Unable to create node");
return -1;
}
new_node->info.idCell=nodeinfo.idCell;
new_node->nextNode = NULL;
list->firstNode = new_node;
list->lastNode = new_node;
list->num_nodes;
return 0;
}
int main()
{
typeNet net;
typeInfoList *list;
// Get memory to store struct with pointers to first & last Nodes
if ((list = (typeInfoList *) malloc (sizeof (typeInfoList))) == NULL)
{
printf ("Error!! Unable to get memory");
exit (1);
}
//Create auxiliar list to store pointers to first & last nodes
initLinkedList (list);
// Sample data to add to first element of the list
net.idCell=5;
//Create initial linked list (first element)
createList (list, net);
}

Answer 1

this
typedef struct StructInfoNodo typeNode;
should be
typedef struct structInfoNodo typeNode;