Copy file byte by byte (Updated)

The program shows you how to copy files byte by byte. Everytime, it reads 4 kbs from the source file and write them in the destination file until it reads all bytes in the srouce file. There is a bar that shows the copying progress, and there is a label that shows the copying percentage. In the new update, you can use the browse button to find the source file you want to copy. I hope you will find the code useful .