Program with Disk Input

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

public class EchoSquareDisk
{
  public static void main (String[] args) throws IOException
  { 
    File    file = new File("myData.txt");   // create a File object
    Scanner scan = new Scanner( file );      // connect a Scanner to the file
    int num, square;

    num = scan.nextInt();
    square = num * num ;   

    System.out.println("The square of " + num + " is " + square);
    scan.close(); 
  }
}

This program reads its data from myData.txt, a text file. The first line of the file contains an integer in character format, such as:

There can be spaces before or after the 12. The Scanner scans over spaces until it finds characters that can be converted to int. It stops scanning when it encounters the first space after the digits. Any additional characters in the file are ignored.

If the file myData.txt does not exist in the current disk directory, or if there are other problems opening it, the Scanner constructor will throw an IOException . Because of this the main() method must declare

throws IOException

An Exception object contains data about what went wrong and can be used for dealing with the problem. This program merely passes the Exception to the runtime system. This is called throwing the Exception.

Answer:

Program with Disk Input

QUESTION 5: