Question

Write a Java program that reads the file "input.txt" and calculates and prints the average of all integer numbers in this file. YOU HAVE TO WRITE 2 VERSIONS: one that throws the FileNotFoundException exception and one that handles the exception (try/catch). Also, make sure that your programs handle (consume) unwanted input. Test your programs in a similar fashion to the output samples listed below.

Answer 1

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class AverageInFile {

    public static void main(String[] args) {
        File file = new File("input.txt");
        try {
            Scanner fin = new Scanner(file);
            double total = 0, count = 0;
            while (fin.hasNextInt()) {
                total += fin.nextInt();
                ++count;
            }
            System.out.println("Average is " + (total/count));
            fin.close();
        } catch (FileNotFoundException e) {
            System.out.println(file.getAbsolutePath() + " is not found!");
        }
    }
}

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class AverageInFile {

    public static void main(String[] args) throws FileNotFoundException {
        File file = new File("input.txt");
        Scanner fin = new Scanner(file);
        double total = 0, count = 0;
        while (fin.hasNextInt()) {
            total += fin.nextInt();
            ++count;
        }
        System.out.println("Average is " + (total / count));
        fin.close();
    }
}