Overwriting a record in a binary file

Hi, here I am trying to overwrite a record in a binary file, however it overwrites the entire file with the write function.  I have attempted to use ios::trunc in the fstream constructor, but still produces same result.

*in this example code i'm simply trying to overwrite the first record, I can retrieve this.
fstream f("records.bin", ios::binary | ios::out);
 
f.seekp(0);
f.write(reinterpret_cast<const char*>(&binPerson),sizeof(binPerson));
f.close();

Open in new window

pangelllAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

sunnycoderCommented:
IIRC this is issue with file opening mode ... You need to open it in rw mode ... opening in w mode truncates it

fstream f("records.bin", ios::binary | ios::out | ios::in);
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
pangelllAuthor Commented:
wow! Thankyou.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
C

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.