Program with `Exception` Handling

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

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

      num = scan.nextInt();  // read and convert the first token
      square = num * num ;   
      System.out.println("The square of " + num + " is " + square);
    }
    catch ( IOException iox ) 
    {
      System.out.println("Error opening the file");
    }
    catch ( InputMismatchException imx ) 
    {
      System.out.println("Bad data in the file");
    }

    if ( scan != null ) scan.close();
    System.out.println("Good-bye");
  }
}

This program catches both Exception types that might arise. If both the creation of the Scanner and the execution of scan.nextInt() worked, then the square of the number is printed out and neither catch block is executed.

At the end of the method, the input stream is closed if is was opened successfully (and therefor not null). Always close a stream when it is no longer needed, but first check that it is open.

Here are some sample runs of the program:

C:\JavaSource> java EchoSquareException
The square of 13 is 169
Good-bye
C:\JavaSource> java EchoSquareException
Bad data in the file
Good-bye
C:\JavaSource> java EchoSquareException
Error opening the file
Good-bye
C:\JavaSource>

Answer:

Program with `Exception` Handling

QUESTION 5:

Answer:

Program with Exception Handling

QUESTION 5:

Program with `Exception` Handling