//FileWriteChars.java

import java.util.Scanner;
import java.io.FileWriter;
import java.io.IOException;

public class FileWriteChars
{
    /* Method closes a FileWriter.
       Prints exception message if closing fails.
     */
    public static void closeFileWriter(FileWriter fileWriter)
    {
        try
        {
            // Ensure fileWriter references a valid object
            if (fileWriter != null)
            {
                System.out.println("Closing file.");
                fileWriter.close(); // close() may throw IOException if fails
            }
        }
        catch (IOException closeExcpt)
        {
            System.out.println
            (
                "Error closing file: "
                + closeExcpt.getMessage()
            );
        }
    }

    public static void main(String[] args)
    {
        Scanner scnr = new Scanner(System.in);
        final int NUM_CHARS_TO_WRITE = 10; // Num chars to write to file
        int countVar; // Track num chars written so far
        FileWriter fileWriter = null; // FileWriter for writing file
        String fileName; // User defined file name
        char charWrite;  // Char data written to file

        countVar = 0;
        charWrite = 'a';

        // Get file name from user
        System.out.print("Enter a valid file name: ");
        fileName = scnr.next();

        try
        {
            System.out.println("Creating file " + fileName + ".");
            fileWriter = new FileWriter(fileName); // May throw IOException

            // Use file output stream
            System.out.print
            (
                "Writing " + NUM_CHARS_TO_WRITE
                + " characters: "
            );
            while (countVar < NUM_CHARS_TO_WRITE)
            {
                fileWriter.write(charWrite);
                System.out.print(charWrite);

                charWrite++; // Get next char ready
                countVar++;  // Keep track of number chars written
            }
            System.out.println();
        }
        catch (IOException excpt)
        {
            System.out.println("Caught IOException: " + excpt.getMessage());
        }
        finally
        {
            closeFileWriter(fileWriter); // Ensure file is closed!
        }
    }
}