How to write and read from binary files

[ChrisW67]

If the files you are using as input are just being treated as a sequence of bytes then you do not need QDataStream, which is more aimed at providing an object serialisation system for Qt applications, you can just use the QIODevice interface directly.

QString::number can convert a byte to its string representation in any base you like between 2 and 36.
QString::toLong can do the opposite magic.

Ultimately I am not sure how useful your experiment will be in getting to your end goal of graphing a data stream from another source.