Programming Challenge 8.4 - Charge Account Validation Modification

/* Charge Account Validation Modification - This program lets the user
   enter a charge account number. The program determines if the number
   is valid by checking for it in the following list:
  
      5658845  4520125    7895122     8777541  8451277  1302850
      8080152  4562555    5552012     5050552  7825877  1250255
      1005231  6545231    3852085     7576651  7881200  4581002

   The list of numbers above is initialized in a single-dimensional array.
   A simple linear search is used to locate the number entered by the user.
   If the user enters a number that is in the array, the program displays
   a message saying that the number is valid. If the user enters a number
   that is not in the array, the program displays a message indicating that
   the number is invalid.

   This program is a modification of Programming Challenge 8.1. It performs
   a binary search to locate valid account numbers. The selection sort
   algorithm is used to sort the array before the binary search is performed. */

#include "Utility.h"

/* Function prototypes */
int getNumber();
void selectionSort(int[], int);
void displaySorted(const int[], int);
void searchNumber(const int[], const int, int);

int main()
{
   /* Number of elements in the array */
   const int NUMELS = 18;

   /* Array initialized with a list of account numbers */
   int accNumbers[NUMELS] = { 5658845, 4520125, 7895122, 8777541,
                              8451277, 1302850, 8080152, 4562555,
                              5552012, 5050552, 7825877, 1250255,
                              1005231, 6545231, 3852085, 7576651,
                              7881200, 4581002 };

   int secretNum = 0;

   selectionSort(accNumbers, NUMELS);

   /* Display the sorted list */
   /* displaySorted(accNumbers, NUMELS); */

   secretNum = getNumber();
   searchNumber(accNumbers, secretNum, NUMELS);

   pauseSystem();
   return 0;
}

/* **********************************************************
   Definition: getNumber

   This function asks the user for his or her secret account
   verfication number and returns it.
   ********************************************************** */

int getNumber()
{
   int secretNum = 0;

   cout << "\n\t\tAshikaga Bank - Credit Authorization Terminal\n\n"
        << "Please enter your secret number: ";
   cin >> secretNum;

   return secretNum;
}

/* **********************************************************
   Definition: selectionSort

   This function accepts accNumbers and NUMELS, containing
   the number of elements in the array, as its argument. It
   performs an ascending order selection sort.
   ********************************************************** */

void selectionSort(int accNumbers[], int NUMELS)
{
   int startScan = 0,
       minIndex = 0,
       minValue = 0,
       index = 0;

   for (startScan = 0; startScan < (NUMELS - 1); startScan++)
   {
      minIndex = startScan;
      minValue = accNumbers[startScan];

      for (index = startScan + 1; index < NUMELS; index++)
      {
         if (accNumbers[index] < minValue)
         {
            minValue = accNumbers[index];
            minIndex = index;
         }
      }

      accNumbers[minIndex] = accNumbers[startScan];
      accNumbers[startScan] = minValue;
   }
}

/* **********************************************************
   Definition: searchNumber

   This function accepts accNumbers, containing a list of int
   numbers secretNumber, and NUMELS as arguments. It performs
   a binary search on the array. If a match has been found,
   the user is informed that his or her entry was valid. If
   no match could be found, a message indicating that the
   secret number was not found is displayed.
   ********************************************************** */

void searchNumber(const int accNumbers[], const int secretNum,
                  int NUMELS)
{
   /* Variables: First array element, Last array element, Midpoint of
                 search, Position of search value */
   int firstElem = 0,
       lastElem = NUMELS - 1,
       midpoint = 0,
       position = - 1;

   /* Flag to indicate a match */
   bool isFound = false;

   while (!isFound && firstElem <= lastElem)
   {
      /* Calculate the midpoint */
      midpoint = (firstElem + lastElem) / 2;

      /* If the arrays midpoint contains the secret number, isFound is set to
         true and position is set to midpoint. Else if accNumbers midpoint is greater
         than secretNum, lastElement is set as new midpoint, otherwise if the
         number is smaller, firstElem is set as the new midpoint to perform the next
         iteration of the search. */
      accNumbers[midpoint] == secretNum ? isFound = true, position = midpoint :
      accNumbers[midpoint] > secretNum ? lastElem = midpoint - 1 :
                                           firstElem = midpoint + 1;

   }

   isFound ? cout << "\nYour secret number has been successfully verified!" :
             cout << "\nYour secret number was not found in our database ...";
}

/* **********************************************************
   Definition: displaySorted

   This function verifies that the list of numbers stored
   in accNumbers has been sorted correctly by displaying its
   contents.
   ********************************************************** */

void displaySorted(const int accNumbers[], int NUMELS)
{
   for (int index = 0; index < NUMELS; index++)
   {
      cout << accNumbers[index] << " ";
      cout << "\n";
   }
}

Example Output: