The idea is to transfor the number stream into the byte stream when storing and back when loading the file.
How easy would this be considering that some numbers can be stored using just 1 byte while others will need 2 bytes? I personally think that he might be better off declaring an array of wide characters, putting all the numbers in the array and write in the file. Reading the data is just as easy, every 2 bytes will represent a number that he could easily retrieve from the file.