/****************************************************************
 *                                                              *
 *      Program 2 - First Skeleton                              *
 *  The program is made modular by use of separate functions.   *
 *  A switch statement is used for the menu.                    *
 *  File input is used to read in numbers of an array.          *
 *                                                              *
 *  Author: David Hume                                          *
 *  Date of Creation: September 29, 2009                        *
 *                                                              *
 *                                                              *
 ****************************************************************/


#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;

   /* Function prototypes allow the main function to call          */
   /* those functions without knowing their internal details.      */
   /* The prototype describes the argument list and return value.  */

void printArray (double x[], int  n); // function prototype
void displayMenu ();                  // function prototype
void readArray (double x [], int &n); // function prototype

int main ()
{
   /* The following variables are visible in the main function.  */

   bool    processAnotherFile = true;
   char    response;
   bool    menuActive;
   char    menuChoice;

   double   x[100];  //array of up to 100 numbers
   int      n;  // counts array elts x[0],x[1],...,x[n-1]

   while (processAnotherFile)
   {

      readArray  (x, n);  // call the readArray function

      menuActive = true;
      while (menuActive)
      {
         displayMenu ();   // call displayMenu function
         cin >> menuChoice; cin.ignore(80,'\n');
         cout << endl;

         switch (menuChoice)
         {
            case '1': case 'P': case 'p':
               printArray (x, n);
               break;
            case '2':
               cout << "Menu Option 2 executed" << endl << endl;
               break;
            case '3':
               cout << "Menu Option 3 executed" << endl << endl;
               break;
            case '4':
               cout << "Menu Option 4 executed" << endl << endl;
               break;
            case '5': case 'Q': case 'q':
               menuActive = false; // Finish this series of menu choices
               break;
            default:
               cout << "       Invalid menu choice: try again!" << endl << endl;
         }  // end switch statement
      }

      cout << "Process another file? y/n : ";
      cin  >> response; cin.ignore(80,'\n');
      if (response == 'n' || response == 'N') processAnotherFile = false;
      cout << endl << endl;
   }  // end while (goAgain) loop

   return 0;
}  // end main function

/****************************************************************
 *                                                              *
 *     This function handles details of reading a 1-dimensional *
 * array of elements of type double.  After prompting for a     *
 * filename, the file is opened, and the numbers are read and   *
 * stored in an array as x[0],x[1],x[2],...,x[n-1].             *
 *                                                              *
 * First argument: the array where numbers are stored -- passed *
 *    by reference (as are all arrays by default).              *
 *                                                              *
 * Second argument: n = number of elements in the array -- also *
 *    passed by reference using the "&" notation.               *
 *                                                              *
 ****************************************************************/
void readArray (double x [], int &n)
{
   int      i;

   char     filename[51]; // room for 50-character path/file name
   ifstream inputFile;    // object declaration: input file stream

   cout << "Enter filename (and path, if needed):" << endl;
   cin.getline (filename, 51);
   cout << endl << endl;

   inputFile.open(filename);

   i = 0;

   while (inputFile.eof() == false)
   {
      inputFile >> x[i];
      if (!inputFile.eof())  // means that x[i] was successfully read
         i++;
   }
   inputFile.clear();  // clear flags associated with the file
   inputFile.close();
   n = i;  // n = number of elements in array

}  // end readArray function

/****************************************************************
 *                                                              *
 *     This function displays a 1-dimensional array of numbers  *
 * of type double in six columns of field width 10 with two     *
 * decimals to the right of the decimal point.                  *
 *                                                              *
 * First argument: the array of numbers is passed by reference, *
 *    as is the case for all arrays.                            *
 *                                                              *
 * Second argument: n = number of elements in the array; this   *
 *    argument is passed by value, meaning that the value comes *
 *    in to the function, but cannot be sent back out.          *
 *                                                              *
 ****************************************************************/
void printArray (double x[], int n)
{
   int i;
   int columnCount;

   cout << endl << endl;
   cout << "Echo of Array Values from Input File:" << endl << endl;
   cout << setprecision(2) << fixed << right;
   columnCount = 0;
   for (i=0; i < n; i++)
   {
      cout << setw(12) << x[i];
      columnCount++;
      if (columnCount == 6)
      {
         columnCount = 0;
         cout << endl << endl;
      }

   }
   cout << endl << endl;
   cout << "Number of elements in array: " << n << endl << endl;
}  // end printarray function


/****************************************************************
 *                                                              *
 *         This function displays the main menu.  There are no  *
 *   input arguments to the function, and no data is returned.  *
 *                                                              *
 ****************************************************************/

void displayMenu ()
{
   cout << "   *************************************************" << endl;
   cout << "   *                                               *" << endl;
   cout << "   *           M A I N    M E N U                  *" << endl;
   cout << "   *                                               *" << endl;
   cout << "   *   1) (P)rint Array                            *" << endl;
   cout << "   *   2) Option 2                                 *" << endl;
   cout << "   *   3) Option 3                                 *" << endl;
   cout << "   *   4) option 4                                 *" << endl;
   cout << "   *   5) (Q)uit: Finish processing this array     *" << endl;
   cout << "   *                                               *" << endl;
   cout << "   *************************************************" << endl;
   cout << "       Enter choice: ";
}  // end displayMenu function