How to write Cyrillic alphabet to file via fstream?

Question

C++ / C#

VS 2019, C++ 20.
I tried a lot of options, I just can't write char / string with Cyrillic to a file.
I get something similar from broken bytes ( Encoding in UTF-8 text editor)
Each character is 2 bytes, broken characters are dw0, dw1

UTF-8 in a text editor

�w�w�w�w�wy1diq�w�wy�w�w�w�w�w�w�w�w

If I put CP1251 in a text editor, it shows this:

CP1251 in text editor

РwРwРwРwСwy1diqРwСwyРwРwРwРwСwРwСwСw,yСw

I tried to put the locale in the write / read stream

locale

locale loc("ru-RU"); fout.imbue(loc);

One attempt to output to a file:

outstream

vector<char> decode = efi.decrypt(enc);

fout.open("3.txt");
for (int i = 0; i < decode.size(); i++)
    fout << decode[i];
fout.close();

Answer 1

https://www.codeproject.com/Articles/38242/Reading...
https://stackoverflow.com/questions/5026555/c-how-...