Question

I’m working on a linked list for school and I am getting a ton of errors. I’m sure there’s probably only one thing wrong with my code, but I can’t seem to find it. I’ve commented out most of my code so I didn’t have to paste like 200 lines in here and the main error is still showing up, although quite a few less times.

The error is:

error C2143: syntax error : missing '{' before '*'    

I had probably 50-75 errors pop up along those guidelines before I commented out my code, but there are still a few with this code. Any help would be much appreciated.

//main.c
#define BUFFER_SIZE 1000
#include<stdio.h>
#include<stdlib.h>
#include"ListElmt.h"
#include"List.h"
#include"ListData.h"

int main(int argc, char *argv[]){
}

//List.c
#include<stdlib.h>
#include"List.h"
#include"ListElmt.h"
#include"ListData.h"

//List.h
struct List{
int size;
struct ListElmt *head;
struct ListElmt *tail;
};

//ListData.h
struct ListData {
int hour;
int min;
double temp;
int AC;
};

//ListElmt.h
struct ListElmt {
ListData *data;
ListElmt *next;
ListElmt *prev;
};

Answer 1

You need to forward declare structures if they aren’t declared in the header file.

Therefore, List.h needs a forward declaration of struct ListElmt, and ListElmt.h needs a forward declaration of struct ListData.

Furthermore, in C you have to use struct before ListData and ListElmt in ListElmt.h since struct names aren’t considered type names unless you use an explicit typedef.