Pls Help [working with files] (noob)

// Terminal login and registration system by me for storing data in binary form in strings upto 1000 characters. // Current Problem : System working for only first registration number that is 0 and password = "sumit". // For other reg numbers its saying incorrect passwords. // NOTE : Please exit program always by proper exit[3]. There are two files in the my directory 1. count.txt 2. data (no extension) (binary encoded)