/*
   testarr14.cpp
   CIS 150
   06/19/2008
   David Klick

   This program demonstrates how to search for information
   in parallel arrays, with the array data coming from a
   data file.
*/

#include <iostream>
#include <iomanip>
#include <fstream>
using std::cin;
using std::cout;
using std::setw;
using std::left;
using std::ifstream;

void cont();
int find(int id[], int length, int idnum);

int main() {
   int n, pos;
   int numrecs = 0;  // number of array elements being used
   const int ARRAY_SIZE = 100;  // must leave more space than needed
   
   // declare arrays of names and IDs
   char names[ARRAY_SIZE][40];
   int id[ARRAY_SIZE];

   // open file containing name and ID data
   ifstream infile("arraydata.txt");
   if (!infile) {
      cout << "Error: Could not open input file\n";
      cont();
      return 1;
   }
   
   // load arrays from file
   infile >> id[0];
   while (infile && numrecs<ARRAY_SIZE) {
      infile.getline(names[numrecs], 40, '\n');
      numrecs++;
      if (numrecs < ARRAY_SIZE) {
         infile >> id[numrecs];
      }
   }
   infile.close();
      
   // loop until user chooses to exit
   do {
   
      // find out which ID # the user wants to display
      cout << "Find which user id? (-999 to exit) ";
      cin >> n;
   
      // display desired name if user didn't choose to exit
      if (n != -999) {
         pos = find(id, ARRAY_SIZE, n);
         if (pos == -1) {
            cout << "Error: ID number not found\n";
         } else {
            // display names associated with ID #
            cout << setw(3) << n << ": " << names[pos] << '\n';
         }
      }
   } while (n != -999);

   cont();   
   return 0;
}

/*
   int find(int id[], int length, int idnum);
   
   Arguments:
      int id[]: holds employee ID numbers
      int length: number of elements in id[] array
      int idnum: employee number to search for
   
   Returns: an integer indicating the position in the id[] array
      where idnum was found, or -1 if idnum was not found
      
   Searches for an ID number within an array of ID numbers
   and returns the position where found, or -1 if not found.
*/
int find(int id[], int length, int idnum) {
   int i;
   for (i=0; i<length; i++) {
      // if found, then return position in array
      if (idnum == id[i]) return i;
   }
   
   // not found, so return -1
   return -1;
}

/*
   void cont();
   
   Arguments: none
   
   Returns: nothing
   
   Clears input buffer and pauses waiting for user 
   to press Enter.
*/
void cont() {
   if (cin.rdbuf()->sungetc() != -1 && cin.get() != '\n') cin.ignore(80,'\n');
   cout << "Press enter to continue...";
   cin.get();
}

/*
   Sample output:
          
   Find which user id? (-999 to exit) 5
   Error: ID number not found
   Find which user id? (-999 to exit) 99
    99:  Bob Hope
   Find which user id? (-999 to exit) 27
    27:  Carol O'Connor
   Find which user id? (-999 to exit) 32
    32:  Ted Danson
   Find which user id? (-999 to exit) 18
    18:  Alice Springs
   Find which user id? (-999 to exit) -999

   Listing of data file:
           
   99 Bob Hope
   27 Carol O'Connor
   32 Ted Danson
   18 Alice Springs
*/