Reading from and writing to same file

okay, hopefully this'll be my last question for the day. I got the hard part of my program done

Basically I'm writing a program that manages a database for a library. it's a data file in this format:

Title
Author
# of copies
Price (in dd.cc form)

what I need to do is be able to add a book to the database without overwriting. so I have two questions:

1) if I simply output the new book to the file will it overwrite the old one?
2) is there a way to send the cursor to the bottom of the file so it starts writing there without using getline?

sorry for starting so many threads today, but I need to get this done

read this fstream tutorial
http://www.daniweb.com/techtalkforum...2&page=1&pp=15
it will answer your questions

Quote:

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2) is there a way to send the cursor to the bottom of the file so it starts writing there without using getline?

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Yes, open the file with the flag ios::app

Code:

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

bool addRec(DBRec *pRec) {
  // open an output stream
  // in binary mode
  // and initialize it with the file pointer ready to append
  ofstream fout("your.db", ios_base::out | ios_base::binary | ios_base::app);

  if (!fout.is_open()) {
    fout.write((const char*)pRec, sizeof(DBRec));
    fout.close();
    return true;
  }
 
  return false;
}

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Also note that you should not use getline() for binary files (but come to think of it, you might be writing records in text mode, in which case ignore the binary part of my example).

[edit]
You might want to look up the following functions:

Code:

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seekg();// move the file pointer
tellg();// returns the current index of the file pointer
seekp();// move the file pointer
tellp();// returns the current index of the file pointer
/* ...g() = input stream, ...p() = output stream */

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[/edit]