// Starter code for prac_q10.
// Create your order management system here!

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

#define MAX_LEN 20

enum order_type { BUY, SELL };

struct order {
    enum order_type type;
    int price;
    int quantity;
    struct order *next;
};

struct order *read_orders(void);

int main(void) {
    struct order *order_list = read_orders();
    // TODO: Implement your solution here!
}

// This function reads in a list of orders, ending with either
// a blank line, or EOF.
// Returns: A pointer to the head of the linked list
struct order *read_orders(void) {
    char line[MAX_LEN];
    struct order *head = NULL;
    struct order *tail = NULL;
    while (fgets(line, MAX_LEN, stdin) != NULL && strcmp(line, "\n")) {
        struct order *new = malloc(sizeof(struct order));
        new->next = NULL;
        char order_char;
        sscanf(line, "%c %d %d", &order_char, &new->quantity, &new->price);
        new->type = (order_char == 'b') ? BUY : SELL;
        if (head != NULL) {
            tail->next = new;
            tail = new;
        } else {
            head = tail = new;
        }
    }
    return head;
}