Мне нужна помощь в понимании моего java кода

I am currently wondering how a certain java program would be written properly.



 [Sample Console Output/File Output][1]
A department store manages their sales in the form of files.  A sale is recorded on each line of a sales file in this format:

22349999990603193150

    The first 4 digits are the department code(2234)
    The next 6 digits are the item number (999999)
    The next 6 digits are the date(060319)
    The final digits are the price in pennies(3150)

Write a program that will parse a sales file and print a report for each sale

Your program should:

    Prompt a user for the input sales file name
    Prompt a user for the output report file name
    Create your own input file with at least 4 items
    Read each line of the sales file
        Print the following to the console and output report file 
            The department store name: MCC Department Store
            The date in format  full month name, day, 4 digit year
            The department name
            The item number
            The price, tax and total
    The department ranges are:
        1000-1999 Clothing
        2000-2999 Hardware
        3000-3999 Food
        4000-4999 Toys
        5000-5999 Sporting Goods
        6000-9999 – Misc.


  [1]: https://i.stack.imgur.com/RMAYp.jpg

My current code is as follows:

    try {
             in = new FileInputStream("input.txt");
             out = new FileOutputStream("output.txt");
             
             int c;
             while ((c = in.read()) != -1) {
                out.write(c);
             }
          }finally {
             if (in != null) {
                in.close();
             }
             if (out != null) {
                out.close();