variable scope question

peterbooth <>
Thu, 9 Apr 2009 11:42:30 -0700 (PDT)
One of my students is having trouble with a Java program and I was
hoping you could answer a quick question. We are currently working
with try/catch blocks.

The student wrote a program (code is below) where she initialized and
used a few variables in the 'try' block and then used them again in
one of her 'catch' blocks.
When she compiled her program she received a message that the
variables "fout" and "inFileName" could not be found. I did a little
research (because this is all new to me also) and I found an internet
reference that says that variables initialized within 'try' blocks
cannot be seen within 'catch' blocks. So I moved the initialization
of these two variables outside the try block. Now the compiler
(BlueJ) is saying that the two variables "might not have been

I'm not sure how to proceed. Can anyone offer any guidance?

Peter Booth

Her code (with initializations moved outside of the try block):

import java.util.Scanner;
public class MonthAbbreviations1
    public static void main(String[]args)
        PrintWriter fout;
        String inFileName;
        String outFileName;
            int start;
            int stop;
            int monthNumber;
            final String MONTH_TABLE = "JanFebMarAprMayJun" +
            String monthAbbrev;

            System.out.println("Enter input file name: ");
            Scanner kbd = new Scanner(;
            inFileName = kbd.nextLine();
            File inFile = new File(inFileName);
            Scanner fin = new Scanner(inFile);

            System.out.println("Enter output file name: ");
            outFileName = kbd.nextLine();
            File outFile = new File(outFileName);
            fout = new PrintWriter(outFile);

            while (fin.hasNextDouble())
                monthNumber = fin.nextInt();
                start = (monthNumber - 1)*3;
                stop = start + 3;
                monthAbbrev = MONTH_TABLE.substring(start,stop);
                fout.println("Month #" + monthNumber + " \nbegins with
'" + monthAbbrev +"'.");

         System.out.print("Done. See " + outFileName);
        catch (IllegalArgumentException iae)
            System.err.println( iae.getMessage() );
        catch (FileNotFoundException fnfe)
            System.err.println("Failed to open file " + inFileName + "
or " + outFileName);
        catch (Exception e)

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