// listpq.cpp - implements class ListPQ
// cmc, 11/1/2013

#include "listpq.h"

// define the list node structure
struct Node {
    double value;
    Node *next;
    Node(double v) : value(v), next(0) { }
};

// only constructor
ListPQ::ListPQ() : list(0) { }

// put maintains the list in sorted order, greatest to least
void ListPQ::put(double value) {
    Node *newNode = new Node(value);
    
    if (!list) // empty list case
        list = newNode;
        
    else if (value >= list->value) { // new node goes in front
        newNode->next = list;
        list = newNode;
    }
    else {
        Node *n = list;
        while(n->next && value < n->next->value)
            n = n->next;
        newNode->next = n->next;
        n->next = newNode;
    }
}
 
// get removes and returns the first (greatest) value
// assumes list is not empty
double ListPQ::get() {
    Node *n = list;
    double result = n->value;
    list = n->next;
    delete n;
    return result;
}