Specific question on seek

Question

Ok here is a specific question unlike my previous one.
If i store records with a fixed record length something like :
RandomAccessFile file = new RandomAccessFile("example.txt","rw");
           long pos = inputLong("Type the record number for saving the data:");I am using the "pos" to give my record a location. Thus searching for a record i would use something like
file.seek(50*pos);My question is, here to locate a record i must know its pos number before hand, is it possible to locate a record with letters instead of a number?

Answer 1

I believe by pos he means "index" or "recordnumber" (i.e. each "record" is 50 bytes long, fixed-width and pos is really which of these records/items he wishes to retrieve).
As far as locating them with letters, that depends. If you simply wish to find a record that contains specific letters, then you will have to read each record and then check if it contains those letters. If, on the other hand, each record has a "key" (i.e. the first two letters of each record must be unique) then you can read through the entire file when you initially access it and create a hashmap containing these keys and there "position" or "index". Then, when the user says give me AZ, you simply retrieve the "index" from the hashmap and read the corresponding record.
Edit: That example I gave you in your ":( Help" thread does exactly this second option.