// remember, to compile you need to have list.C, list.h, and labex1.C
//    all in the same directory
// the outline below is for list.C,
//    I have provided list.h and labex1.C on the lab page
//
// the compile command is
//    g++  -Wall  labex1.C  list.C  -o labex1
//
// to run the program without an input file use
//    ./labex1
// to run the program and have it read from an input file use
//    ./labex1   yourfilename

// =============== list.C outline ==========================

#include <fstream>
#include "list.h"
using namespace std;

// insertEntry
// -----------
// adds one key/value pair to the front of the list
//    as long as the key does not already appear in the list
// returns true if successful, false otherwise
bool insertEntry(string key, string value, keyValue* &list)
{
   // try lookup on key, list 
   // and if it returns anything except null then return false
   
   // allocate a new keyvalue, store the pointer in a vaiable
   // and if it returns null then return false
   
   // set all four fields in the new item
   // (including copying list to the next field) 

   // if list is null just make it point at the new item
   // otherwise make list's prev field point at the new item
   // return true
}


// lookupEntry  (internal use)
// -----------
// search the list or an entry matching the specified key,
//    return a pointer to the entry if found,
//    return null otherwise
keyValue* lookupEntry(string key, keyValue* list)
{
   // set up a pointer variable and make it a copy of list
   // while that variable isn't null,
   //   if its key matches what you're looking for then return the pointer
   //   otherwise make the variable point to the next item
   // if you get out of the while loop just return null
}


// lookupEntry  (public use)
// -----------
// search the list or an entry matching the specified key,
//    set the matching value and return true if found,
//    return false otherwise
bool lookupEntry(string key, string &value, keyValue* list)
{
   // call lookupEntry to find the right keyValue item   
   // if it is null return false
   // otherwise set value equal to the item's value
   //    and return true
}


// changeEntry
// -----------
// search the list or an entry matching the specified key,
//    set the new value and return true if found,
//    return false if an entry for the key is not found
bool changeEntry(string key, string &value, keyValue* list)
{
   // call lookupEntry to find the right keyValue item   
   // if it is null return false
   // otherwise set the item's value equal to the parameter value
   //    and return true
}


// deleteEntry
// -----------
// search the list or an entry matching the specified key,
//    remove the entry from the list, delete it, 
//       and return true if found,
//    return false otherwise
bool deleteEntry(string key, keyValue* &list)
{
   // call lookupEntry to find the right keyValue item
   // if it is null return false
   // otherwise
   //    if the item's prev field is null
   //       then set list to the item's next field
   //       (since we're getting rid of the old front item)
   //    otherwise
   //       get the previous item and set it's next field
   //          to be the same as the current item's next 
   //    if the item's next field isn't null
   //       get the next item and set it's prev field 
   //          to be the same as the current item's prev
   //    return true
}


// displayEntries
// --------------
// display each key/value pair in the list,
//   with one key/value pair per line of output
void displayEntries(keyValue* list)
{
   // declare a pointer var and copy the list parameter to it
   // while it isn't null
   //    print that item's key and value, and
   //    set the item to point to the next item
}


// insertFromFile
// --------------
// if the specified file cannot be opened return -1,
// otherwise
//     add each key/value pair in the file to the list
//     returning a count of the total number of successful inserts
// assumes the file contains an even number of lines, 
//    alternating between keys and numbers, e.g.
//                Fred Jones
//                555-123-4567
//                Scoobert Doo
//                555-987-6543
//     etc.
int insertFromFile(char filename[], keyValue* &list)
{
   // create a variable to count the successful inserts,
   //    initializing it to zero
   // declare an ifstream variable
   // open the file
   // if the open failed return -1
   // otherwise
   //    while not at the end of the file
   //       read one line of text into a char array (for the key)
   //       if not at the end of the file
   //          read one line of text into another char array (for the value)
   //          if not at the end of the file
   //             call insert on the key/value, and
   //             if it returned true increment the number of inserts
   //    close the file
   //    return the number of inserts
}