Linked list storing prime numbers from 1 to 1000 - c

Question

As you will see in the comments of the following program, I am supposed to create a list that stores all prime numbers from 1 to 1000 and free the node.
Only two of of the functions are my work. However, I haven't figured out for ages why this program does not compile. Do you guys see the mistake? This is an already handed in homework, so this is just for my personal reference.
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
/* given data structure declaration */
struct record {
int data;
struct record * next;
};
typedef struct record RecordType;
/* DO NOT MODIFY */
/* print a list */
void print_list(RecordType * list)
{
RecordType * visitor = list;
int count = 0;
while (visitor != NULL)
{
printf("%d ", visitor->data);
visitor = visitor->next;
count++;
}
printf("\n");
printf("There are %d items in the list.\n", count);
}
/* MY WORK HERE */
/* free every node in the list */
void free_list(RecordType * list)
{
while (list->data != 2){
free(list->next);
list->next = list;
}
}
/* MY WORK HERE */
/* this function may call other functions created by students */
/* create a list storing all prime numbers in [1, 1000] in ascending order */
/* return a pointer to the starting point of the list */
RecordType * create_list_prime_in_1_to_1000()
{
RecordType * begin, *tail, *temp;
int i = 0;
begin = malloc(sizeof(RecordType));
begin->data = 0;
begin->next = NULL;
tail = begin;
while(i<1000){
temp = malloc(sizeof(RecordType));
temp -> data = ++i;
tail -> next = temp;
tail -> temp;
tail -> next = NULL;
}
}
int isPrime(int n){
int d;
for (d = 2; d < n; d = d + 1)
if (n % d == 0)
return 0;
return 1;
}
/* DO NOT MODIFY */
/* main program */
int main(void)
{
RecordType * start;
/* create a linked list to store all the prime numbers in 1 - 10 */
/* this is a naive way by hard-coding */
start = malloc(sizeof(RecordType));
start->data = 2;
start->next = malloc(sizeof(RecordType));
start->next->data = 3;
start->next->next = malloc(sizeof(RecordType));
start->next->next->data = 5;
start->next->next->next = malloc(sizeof(RecordType));
start->next->next->next->data = 7;
start->next->next->next->next = NULL;
print_list(start);
free_list(start);
/* i am expected to expected to build a list iteratively rather than hard-code */
start = create_list_prime_in_1_to_1000();
print_list(start);
free_list(start);
return 0;
}

Answer 1

You have tail declared as:
RecordType * begin, *tail, *temp;
and RecordType as:
struct record {
int data;
struct record * next;
};
typedef struct record RecordType;
Next you have:
tail -> temp;
which does not work as RecordType has no member named temp.
I think it should be:
tail = temp;
The cause for the runtime error seems to be because of:
void free_list(RecordType * list)
{
while (list->data != 2){
free(list->next);
list->next = list;
}
}
which is incorrect. You need something like:
void free_list(RecordType * list)
{
// keep going till there are nodes.
while (list){
// save the link to the rest of the nodes.
RecordType *temp = list->next;
// free the current node.
free(list);
// repeat the process starting at the next node.
list = temp;
}
}