QFile - QDataStream read and write each character

I want to read every byte of a file and writes each byte in the file just read what others have to use

I did understand nothing. Maybe I poor in english, or your text is senceless. Read your post by my eyes, and say, can I understand what you want ?

QFile documentation has some good examples of reading and writing QFile's, and using QDataStream with it is pretty easy and also documented. There are also examples in the Qt dir.