How do I write an integer to a file without it being seen as the associated ascii character when being turned into bytes?
You can use for example
42u64.to_le_bytes() (returns little endian bytes) there is a similar method for big endian (
to_be_bytes) This works for all integer types.
42u64.to_le_bytes() will include the byte 42 in its output, which will appear as the character
* (asterisk) if interpreted as ASCII.
Every byte may be interpreted as some character if a program incorrectly interprets it as text. If you want your file to contain human-readable text instead of seemingly-random characters when opened in a text editor, you can serialize your data to a text-based format like JSON or CSV before writing it to a file.
A binary format is often more compact, and usually faster to read and write, but it is not friendly to text editors or other programs that expect the file to contain text.
What is your goal? There are a number of ways to interpret your question as you've asked it.