#define ALLOW_INSTRUCTOR_CODE
/***************************************************************************
 ***************************************************************************
 ****** BEFORE BEGINNING OR TURNING IN THIS EXERCISE IT IS  EXTREMELY ******
 ****** IMPORTANT THAT YOU READ, FULLY UNDERSTAND, AND ADHERE TO  THE ******
 ****** REQUIREMENTS STATED  IN  THE  DOCUMENT  TITLED,   "ASSIGNMENT ******
 ****** SUBMISSION REQUIREMENTS", DOWNLOADABLE FROM  THE  COURSE  WEB ******
 ****** SITE.                                                         ******
 ***************************************************************************
 **************************************************************************/



/***************************************************************************
 ************* C/C++ Programming 2:  Assignment 8 - Exercise 1 *************
 ******** BEGIN EXERCISE REQUIREMENT - THIS MUST BE A "C++" PROGRAM ********
 ***************************************************************************

   (5 points)  Write functions OpenFiles and MergeAndDisplay:
   
      OpenFiles syntax:
         ifstream *OpenFiles(char * const fileNames[], size_t count);
      Parameters:
         fileNames - a pointer to the first element in an array representing
                     the names of text files to be opened.  The array has
                     the underlying format:
                         char *fileNames[] = { "fileA", "fileB", etc. };
         count -     the number of elements in <fileNames>
      Synopsis:
         Dynamically creates an array of <count> ifstream objects then uses
         them to open the files named in <fileNames>, in order.  All opens
         are in the read-only text mode.  If any open fails all previously
         opened files are closed, the dynamic allocation is deleted, an
         error message is output to cerr, and the program is terminated with
         an error exit code.  If <count> is zero an error message is output
         to cerr and the program is terminated with an error exit code.
      Return:
         a pointer to the first entry in the ifstream array if <count> is
         non-zero and all opens succeed; otherwise, the function does not
         return.


      MergeAndDisplay syntax:
         void MergeAndDisplay(ifstream files[], size_t count);
      Parameters:
         files -  a pointer to the first element in an array of <count>
                  ifstream objects, where each object represents a text
                  file open in the text mode for reading.
         count -  the number of elements in the array in <files>
      Synopsis:
         Proceeding in order from the first file specified in <files>, the
         first line in each is read and displayed, followed by the second
         line in each, follow by the third, etc.  When the end of any file
         is reached that file is closed and the process continues using only
         the remaining open files, until all files have finally been closed.
         Empty lines are displayed as empty lines.  Empty files are simply
         closed and ignored.
      Return:
         void


   * Specify the file name(s) on the command line.
   * Both functions must handle any arbitrary number of files.
   * Assume no line will contain more than 511 characters.
   * Do not attempt to store the entire contents of any file.     
   * Do not attempt to read a file after reaching its EOF.
   * Use files "mFile1.txt" through "mFile5.txt", downloaded from the
     course web site to test your program with the following two command
     lines:

         mFile1.txt  mFile2.txt  mFile3.txt  mFile4.txt  mFile5.txt
         mFile3.txt  mFile2.txt  mFile1.txt


   Example:  If the command line specifies:  f1  f2  f3
             and those files contain the following text:
   
   File Name:      f1                  f2                  f3
    Line 1:        Hello from          Bah bah black       Now is
    Line 2:        the                 sheep               the
    Line 3:        other side of       <EOF>               time for all
    Line 4:                                                good men and
    Line 5:        the universe                            <EOF>
                   <EOF>
                   
   the display would be:
   
      Hello from
      Bah bah black
      Now is
      the
      sheep
      the
      other side of
      time for all

      good men and
      the universe

   Hint:
      * Place all input test files in the appropriate default location
        described in the "FILE LOCATION QUESTIONS AND ANSWERS" section
        of the "ASSIGNMENT SUBMISSION REQUIREMENTS" document.

 ***************************************************************************
 ************************ END EXERCISE REQUIREMENT *************************
 **************************************************************************/



/***************************************************************************
 * BEFORE PRINTING THIS ASSIGNMENT  TO  TURN  IN, DELETE  THIS  COMMENT  AND
 * EVERYTHING ABOVE IT.
 **************************************************************************/

/*
 * TODO:
 *   REPLACE THIS COMMENT WITH YOUR TITLE BLOCK.
 */

/*
 * TODO:
 *    REPLACE THIS COMMENT WITH YOUR C++ CODE, PLUS  ANYTHING  NECESSARY  TO
 *    SUPPORT MY TEST CODE BELOW.  DO NOT INCLUDE ANY UNNEEDED HEADER FILES!
 */

/***************************************************************************
 * BEFORE PRINTING THIS ASSIGNMENT  TO  TURN  IN, DELETE  THIS  COMMENT  AND
 * EVERYTHING BELOW IT.
 **************************************************************************/

/*
 ***** Change nothing below this comment without instructor permission. ****
 * Everything that follows was written to help test/verify your code.  You
 * do not need to understand the details of my code to write yours!
 */
#ifdef ALLOW_INSTRUCTOR_CODE
int main(int argc, char *argv[])
{
   ifstream *files = OpenFiles(&argv[1], size_t(argc - 1));
   MergeAndDisplay(files, size_t(argc - 1));
   delete[] files;

   return EXIT_SUCCESS;
}
#endif