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

struct node
{
        int info;
        struct node *next;
};
typedef struct node node;

node *inserthead(node *head, int a){
        node *ptr;
        ptr = (node*)malloc(sizeof(node));
        ptr->info = a;
        ptr->next = head;
        return(ptr);
}

node *deletemultiples(node *head, int k){
        node *ptrcur = head, *ptrlast = ptrcur, *deletethis;
        while (ptrcur != NULL){
                if(ptrcur->info != k && ptrcur->info%k == 0){
                        ptrlast->next = ptrcur->next;
                        deletethis = ptrcur;
                        ptrlast = ptrcur;
                        ptrcur = ptrcur->next;
                        free(deletethis);
                }
                else{
                ptrlast = ptrcur;
                ptrcur = ptrcur->next;
				}
        }
        return(head);
}

void printlist (node *head){
        while (head != NULL){
                if (head->next != NULL)
                printf("%d, ", head->info);
                if (head->next == NULL)
                printf("%d",head->info);
                head = head->next;
        }
        printf("\n");
}

void freelist (node *head){
        node *del = head;
        while(head != NULL) {
                head = head->next;
                free(del);
                del = head;
        }
}

int main(){
        int i;
        node *head = NULL;

        // This for loop creates the initial list of all integers 2-1000.
        for (i = 1000; i > 1; i--){
                head = inserthead(head, i);
        }

        // This deletes all multiples of all numbers between 1-32 from the list.
        if(head != NULL){
        for (i = 2; i <= 32; i++){
                deletemultiples(head, i);
        }

        // This prints the list, which should be the primes.
        printlist(head);
        freelist(head);
    }
}