/* Filename:  makepart.cpp

   Author:  Br. David Carlson

   Date:  February 23, 1998

   Revised:  July 4, 1998

   Revised:  July 16, 2000 to use modern headers.

   This program creates a binary file of parts records.  The data for
   each record consists of an ID number, number in stock, price, and
   description, and is read from the keyboard and written to this
   binary file, called parts.dat.
*/

#include <fstream>   // needed for files
#include "parts.h"  // needed for PartType


const int MaxString = DescripMax;

typedef char StringType[MaxString];


/* Given:  InStream     An input file stream already open for reading.
           StringMax    The maximum number of characters that can be put
                        into String, including the NULL that marks the
                        end of the string.
   Task:   To read up to StringMax - 1 characters from InStream, storing
           them in String, but stopping if a newline is read or end of
           file or an error condition is reached.
   Return: String       The string just read, with a NULL appended to
                        mark the end of the string.  If a newline was
                        read, it is not stored in String.
           The number of characters read into String (not counting the NULL)
           is returned in the function name.
*/
int MyGetLine(istream & InStream, char * String, int StringMax)
   {
   char Ch;
   int Count, Last;

   Count = 0;
   Last = StringMax - 1;
   Ch = InStream.get();

   while ((Ch != '\n') && (! InStream.fail()))
      {
      if (Count < Last)
         String[Count++] = Ch;
      Ch = InStream.get();
      }

   String[Count] = NULL;
   return Count;
   }


/* Given:   fs   A binary file stream already opened for output.
   Task:    To read parts data from the user, writing each record of
            accumulated data to fs.
   Return:  fs   The modified file stream.
*/
void WriteToFile(fstream & fs)
   {
   int RecordSize, Number;
   PartType Part;

   RecordSize = sizeof(Part);
   cout << "Enter a part number (or 0 to exit): ";
   cin >> Number;

   while (Number != 0)
      {
      // Put data into the Part record:
      Part.ID = Number;
      cout << "Enter number in stock: ";
      cin >> Part.NumInStock;
      cout << "Enter price: ";
      cin >> Part.Price;
      cin.get();  // input newline at end of price
      cout << "Enter description: ";
      MyGetLine(cin, Part.Descrip, DescripMax);

      // Write the Part record to the binary file:
      fs.write(reinterpret_cast <char *> (&Part), RecordSize);
      
      cout << "Enter a part number (or 0 to exit): ";
      cin >> Number;
      }
   }


int main(void)
   {
   fstream PartFile;

   PartFile.open("parts.dat", ios::out | ios::binary);
   if (PartFile.fail())
      {
      cerr << "Could not create file parts.dat" << endl;
      exit(1);
      }

   WriteToFile(PartFile);
   PartFile.close();

   return 0;
   }