Question

I need help figuring out how to loop my IOException (in where I ask for a filename until a valid one is entered). I need a loop that somehow recognizes that an invalid file was entered and am unsure how to do this.

import java.util.*;
import java.io.*;
public class JavaGradedLab {
    public static void main(String[] args) throws IOException {

        Scanner inScan, fScan = null;
        int [] A = new int[5];
        inScan = new Scanner(System.in);
        System.out.println("Please enter the file to read from: ");

        try{
            String fName = inScan.nextLine();
            fScan = new Scanner(new File(fName));
        }

        catch (FileNotFoundException ex)
        {
            System.out.println("Your file is invalid -- please re-enter");
        }

        String nextItem;
        int nextInt = 0;
        int i = 0;

        while (fScan.hasNextLine())
        {
            nextItem = fScan.nextLine();
            nextInt = Integer.parseInt(nextItem);
            A[i] = nextInt;
            i++;
        }

        System.out.println("Here are your " + i + " items:");
        for (int j = 0; j < i; j++)
        {
            System.out.println(A[j] + " ");
        }
    }
}

Answer 1

Well, there’s sure to be someone explaining how to make your code better via best practices etc., but as a very basic answer which in itself can probably be improved (assuming that your code works when the input is valid):

while(true) {
    try{
        String fName = inScan.nextLine();
        fScan = new Scanner(new File(fName));
        break;
    }
    catch (FileNotFoundException ex)
    {
        System.out.println("Your file is invalid -- please re-enter");
    }
}