Now, I understand the concept. I hardly ever used hex editors or viewers. So, I am definitely not an expert. But, can you tell me for what reason do I need to edit .cpp files in hex editor? I always thought that hex editor is used to edit pure binary files like .exe or .out.
For example: .cpp file is generated by code or adopted from public domain, there is some string in it and it contains invalid utf-8 sequence. You might need hexview to find out what is going on (what bytes exactly are there).