Easily convert file sizes to human-readable form
If you write an application that has anything to do with file management, you will probably need to display the size of the files. But if a file has a size of 123456789 bytes, it doesn’t mean that you should just display this value to the user, because it’s hard to read, and the user usually doesn’t need 1-byte precision. Instead, you will write something like 118 MB.
This should be a no-brainer, but there are actually a number of different ways to display byte sizes… For instance, there are several co-existing conventions for units and prefixes: