ofstream and binary files.

[801119]

Hey all...!

I found out a nice thing while going trough a friends C++ education disk.
It was 'ofstream writedata(filnamn,ios::binary|ios::app);' though I have little knowledge what it does I am quite sure it writes / reads data in binary form. I tried to write and I wrote in binary (I think). I searched the help files in BCB 3 but found nothing about ofstream
In my previous program I stored data in plain text, which I do not like due to the fact that one can easily manipulate that file.
The program main function is to store Internet connection time in a 'user'.txt file.
One file could look like this

#0,1125 // float number, the # is to find the float number [payment per minute]
¤SEK // string, the ¤ is to find the string [currency]
2000-09-01 02 30 // date (int)hours (int)minutes, hours and minutes connected that date
2000-09-02 00 20 // date (int)hours (int)minutes, hours and minutes connected that date

First I have a function that finds either '#' or '¤' and stores value in a label (or other) or if it finds a 'date' then it will get hours and minutes in that line and store them in a totalHours / totalMinutes integer, for now I store a row in the file as a string then gets two values at specific positions,

line=(AnsiString)row; // A row in the file using while(fget(row,81,file))
hour=line[12];
hour+=line[13]; // this would result in 02 in above files first 'date' row

I am unable to use SubString;

Can anyone help me recreate the function that gets stored information form a binary file?
I not so familiar with this 'ofstream writedata(filnamn,ios::binary|ios::app);'

One last question: When a binary file is opened with ofstream, can I then search for a specific value (numeric or string)? If so, How?

All suggestions are welcome!

Thanks in advance Martin!
[sig]<p>Martin G Broman<br><a href=mailto:mgb_svea@hotmail.com>mgb_svea@hotmail.com</a><br><a href= > </a><br>DWS - Alpha Whitin Dead Wolf Society[/sig]

 

[2ffat]

[tab]ofstream is standard C++. You can probably find more info about that in a book about the C++ standard. (I'd recommend C & C++ Code Capsules by Chuck Allison and there are many others, too). What ofstream does is open an output file stream.ifstream does the opposite, it opens a file stream for input. Personally, I prefer streams to the C versions of fget & fput but many people prefer the C versions over streams. They accomplish the same thing.

[tab]The only difference between binary and &quot;text&quot; mode is how the end of the line is stored in the file. For example, in DOS text mode, file lines are appended with a &quot;\r\n.&quot; In binary mode, no translation is done. An ascii file is still readable with a text editor not matter whether it is &quot;binary&quot; or &quot;text.&quot;

[tab]If you want to &quot;encrypt&quot; a file, the easiest way it to XOR each character before putting it into a file. You will then need to XOR the characters again when you read the file.

[tab]To search for a specific value, you will need to parse the line that is read. You can do this either by looking for a specific number of characters or, it the line was stored with delimiters, for a specific number of delimiter. It will depend on how the line was stored.
[sig]<p>James P. Cottingham<br><a href=mailto: > </a><br><a href=

http://www.ivcusa.com>International

Veneer Co., Inc.</a><br>All opinions are mine alone and do not necessarily reflect those of my employer.[/sig]

 

[801119]

I am not so familiar with XOR, but i asume it would take allot of coding to get it work correctly in my program!
But I will try it, thanks!

If i don't get i to work then i'll just go with ASCII file style! [sig]<p>Martin G Broman<br><a href=mailto:mgb_svea@hotmail.com>mgb_svea@hotmail.com</a><br><a href= > </a><br>DWS - Alpha Whitin Dead Wolf Society[/sig]