// sum_of_positive_negative.c
//
// Written by YOUR-NAME (YOUR-ZID)
// on TODAYS-DATE
//
// Calculates the sum of positive and negative numbers in an array.

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

// DO NOT CHANGE THIS STRUCT
struct node {
    struct node *next;
    int          data;
};

// MODIFY THIS FUNCTION
// sum_of_positive_negative takes in the head of a linked list and calculates 
// the sum of positive and negative numbers
void sum_of_positive_negative(
    struct node *head, 
    int *positive_sum, 
    int *negative_sum
) {
    // TODO: Complete this function
}

////////////////////////////////////////////////////////////////////////
// DO NOT CHANGE THESE PROTOTYPES
////////////////////////////////////////////////////////////////////////
struct node *args_to_list(int argc, char *argv[]);
void print_list(struct node *head);
void free_list(struct node *head);

// DO NOT CHANGE THIS FUNCTION
int main(int argc, char *argv[]) {
    struct node *head = args_to_list(argc, argv);

    printf("LIST: ");
    print_list(head);

    int positive_sum;
    int negative_sum;
    sum_of_positive_negative(head, &positive_sum, &negative_sum);

    printf("Positive sum: %d\n", positive_sum);
    printf("Negative sum: %d\n", negative_sum);

    free_list(head);

    return 0;
}

// DO NOT CHANGE THIS FUNCTION
// Converts command-line args to a linked list of integers
struct node *args_to_list(int argc, char *argv[]) {
    struct node *head = NULL;
    for (int i = argc - 1; i >= 1; i--) {
        struct node *new = malloc(sizeof(struct node));
        new->data = atoi(argv[i]);  
        new->next = head;
        head = new;
    }
    return head;
}

// DO NOT CHANGE THIS FUNCTION
// Prints a linked list of integers
void print_list(struct node *head) {
    struct node *curr = head;
    if (curr == NULL) {
        printf("NULL\n");
        return;
    }
    while (curr != NULL) {
        printf("%d", curr->data);
        if (curr->next != NULL) {
            printf(" -> ");
        }
        curr = curr->next;
    }
    printf(" -> NULL\n");
}

void free_list(struct node *head) {
    struct node *curr = head;
    while (curr != NULL) {
        struct node *to_free = curr;
        curr = curr->next;
        free(to_free);
    }
}