Question

Modify your program in Lab Assignment 4A to throw an exception if the file does not exist. An error message should result.   Use the same file name in your program as 4A, however, use the new input file in 4B assignment dropbox.

My code:

import java.io.*;
import java.util.*;

public class Lab4B
{
public static void main(String[] args) throws IOException {
final String input_file = "Lab_4A.txt";
final String output_file = "Lab_4A.txt";
Scanner x = null;
FileWriter y = null;

try {
x = new Scanner(new File(input_file));
} catch (FileNotFoundException e2) {
System.out.println("The file " + input_file + " doesn't exist.");
throw e2;
}

try {
y = new FileWriter(output_file);
} catch (IOException e2) {
System.out.println("Unable to output to " + output_file + ".");
throw e2;
}

int count = 1;

while (x.hasNextLine()) {
String line = String.format("%d. %s\n", count++, x.nextLine());
System.out.print(line);
y.write(line);

}
y.flush();

y.close();
x.close();
}

}

Answer 1

Save it as Module_4B_lab_assignment.java import java.io.*; import java.util.*; public class Module_4B_lab_assignment { public static void main(String[] args) throws IOException { final String input_file = "Lab_4A_Input.txt"; final String output_file = "Lab_4A_Output.txt"; Scanner x = null; FileWriter y = null; try { x = new Scanner(new File(input_file)); } catch (FileNotFoundException e2) { System.out.println("The file " + input_file + " doesn't exist."); throw e2; } try { y = new FileWriter(output_file); } catch (IOException e2) { System.out.println("Unable to output to " + output_file + "."); throw e2; } int count = 1; while (x.hasNextLine()) { String line = String.format("%d. %s\n", count++, x.nextLine()); System.out.print(line); y.write(line); } y.flush(); y.close(); x.close(); } }