Trying to make linkedlist in C

Question

I am trying to make a struct in C that is a linked list. I am not really sure what is going wrong though. My errors are:

linked.c:6:2: error: unknown type name         


        

Answer 1

A few observations,

• declare a struct name so that you can use it in the linkedList struct.
• DRY - Don't Repeat Yourself, that is why the below ListNew() function is provided
• use pointers, that is the whole point to building a linked list anyway,
• your list uses one type of node, storing data and the list pointer,
• name the pointer to the next node in the list whatever you want, how about 'next'?
• name the thing that holds data anything you want, how about 'data'?
• print the list, it will help figure out what is going on, :-)
• a pointer can be printed in hexadecimal using the %x print format

Anyway, here is a single linked list, without keeping track of the tail of the list, or counting the elements.

#include 
#include 

typedef struct listnode
{
    int data;
    struct listnode* next;
} linkedList;
linkedList* makeList(int a, int b, int c);
void addToList(linkedList* ll, int a);
void ListPrint(linkedList* ll);
int main()
{
    linkedList* ll = makeList(1,3,5);
    addToList(ll, 7);
    addToList(ll, 9);
    ListPrint(ll);
    return 0;
}
linkedList* ListNew(int a) //new linkedList node
{
    linkedList* newL = (linkedList*)malloc(sizeof(linkedList));
    newL->data = a;
    newL->next = NULL;
    return newL;
}
linkedList* makeList(int a, int b, int c)
{
    linkedList* ll = ListNew(a);
    addToList(ll, b);
    addToList(ll, c);
    return ll;
}
void addToList(linkedList* ll, int a)
{
    if(!ll) return;
    //find end of list
    while (ll->next)
    {
        ll = ll->next;
    }
    ll->next = ListNew(a);
    return;
}
void ListPrint(linkedList* ll) //print list
{
    if(!ll) return;
    linkedList* p;
    for( p=ll; p; p=p->next )
    {
        printf("%x: %d\n",p,p->data);
    }
    return;
}