How can I use C++ to eliminate the BOM in a notepad .txt file?

Question

I want to read in a .txt file using ifstream fin from library fstream, but there is a BOM at the beginning of the file that is causing problems. Is there a way I can, from inside my C++ program, eliminate the BOM in the .txt file, so that fin can read it without any issues? I know I can manually delete the BOM in the file myself, but I have multiple files I'm working with so this will take a while.

My question is similar to this one here, except this one deals in Java:

How to make Notepad to save text in UTF-8 without BOM?

The answer from korifey is what I am looking for, where they said:

Use PushbackInputStream(in, 3)

Is there something similar I can do in C++ ? It should also be noted that I only have Notepad (not Notepad++), and it is preferable to solve my problem without downloading any new software. I also don't want to change how Notepad itself views BOMs, I just want to physically delete the BOM from my .txt file. The BOM I'm dealing with is the first 8 characters.

[std::istream::ignore](http://en.cppreference.com/w/cpp/io/basic_istream/ignore)? — Galik, Jan 01 '18 at 05:45
@Galik I'm not familiar with that command, what would it do? — Inertial Ignorance, Jan 01 '18 at 05:46
I see, it'll ignore the first line when encountering an error. Thanks, that should work. — Inertial Ignorance, Jan 01 '18 at 05:49
If you show the code you are using to read in the file it would be easier for someone to give you a specific answer. — Galik, Jan 01 '18 at 05:52
If you are reading `UTF-8` it is likely to be something like `file.ignore(3);` (`BOM` is three bytes). — Galik, Jan 01 '18 at 05:55
I used fin.ignore(256, ' '); because I wanted to start reading when reaching a space character, which would be after the BOM. For some reason the BOM I had was 7 or 8 characters, and not 3 like I've been seeing many people say. — Inertial Ignorance, Jan 01 '18 at 06:12
@InertialIgnorance, Then it's not a UTF-8 BOM. That's `EF BB BF`, which is three bytes. — chris, Jan 01 '18 at 06:18

score 0 · Answer 1 · answered Jan 01 '18 at 05:56

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This would be easiest by opening the file in binary mode, reading all the data and copying everything but the BOM to a different file, then removing the old file and finally renaming the new file back to the name of the old.

answered Jan 01 '18 at 05:56

SoronelHaetir

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I'll probably use the fin.ignore() function like Galik mentioned, just because it seems a bit quicker. Out of curiosity though, how would I read the file in binary mode, and then copy everything but the BOM to a different file? The only way I could think of to store the data is in an int, but that's base 10. – Inertial Ignorance Jan 01 '18 at 06:02

How can I use C++ to eliminate the BOM in a notepad .txt file?

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