Thread: FILE I/O. data written at wrong location.

I got a series of functions that are connected too eachother, and that write in a certain data file, but when I look into the data file, the data entered isnt where it is supposed too be! it always writes itself in the back of the file

this is the code:

Code:

  std::ofstream WriteIt ("C:\Datacab.dat", ios::app | ios::binary );
  WriteIt.seekp ( ( (Location)* sizeof (member) ), ios::beg );
  std::cout <<"location in bytes: "<<  (Location)* sizeof (member) << std::endl;
  WriteIt.write ( ( reinterpret_cast < char * > (&Wthis) ),sizeof (member) );

I am 100% sure that somthin is wrong RIGHT THERE since this is what i got as output checking:

Code:

Location: LOOP -> 1
Registered!!
location in bytes: 0

wheras Location represents the times looped untill the place is found where the data must written, we do minus 1 (-1) to get the exact location in the file that needs too be overwritten. this is shown by : location in bytes -> 0

but it just doesnt write there! help?!
instead it just allways APPENDS on the back of the file, increasing it size too!! which isnt what i want

can i ask, what the diffrence between .bin files and .dat files are?
and i also solved my problem this way:

Code:

std::fstream WriteIt ("C:\Datacab.dat", ios::in | ios:ut | ios::binary );

but i can explain why that does work.