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

/** Demo exceptions.
    @author Jed Yang, 2018-01-15
*/
public class ExceptionDemo
{
   /** This method might throw an exception if denominator is 0, because
       dividing by 0 is bad for the universe.
   */
   public static int ratio(int numerator, int denominator)
   {
//*
      if (denominator == 0)
      {
         System.err.println("Should not divide by 0.  Bye!");
//         System.exit(2);
         throw new RuntimeException("Eh, the universe just exploded.");
      }
//*/
      return numerator/denominator;
/*
      try
      {
      }
      catch (ArithmeticException e)
      {
         System.err.println("Something went wrong.");
         return -1;
      }
//*/
   }

   public static void main(String[] args)
   {
      int top = 0;
      int bottom = 0;
      Scanner kb = new Scanner(System.in);

      try
      {
         System.out.print("Integer, please: ");
         top = kb.nextInt();
         System.out.print("Positive integer, please: ");
         bottom = kb.nextInt(); 
//*
      }
      catch (java.util.InputMismatchException e)
      {
         System.err.println("Please type an integer next time.  Bye!");
         System.exit(1);
      }
//*/

//*
      try
      {
         System.out.println("The ratio is: " + ratio(top, bottom));
      }
      catch (ArithmeticException e)
      {
         System.err.println("I caught the exception outside!");
      }
//*
      catch (RuntimeException e)
      {
         System.err.println("I am catching the exception I threw, with message: " + e.getMessage());
      }
//*/
      
//      readFromFile();
   }

   /** Removing the try-catch block will require adding 'throws
       FileNotFoundException' to the method declaration.
   */
   public static void readFromFile() throws FileNotFoundException
   {
      String inputFilePath = "somelines.txt";
      File inputFile = new File(inputFilePath);

      Scanner scanner = null;
      scanner = new Scanner(inputFile);
/*
      try
      {
      }
      catch (FileNotFoundException e)
      {
         System.err.println(e);
         System.exit(1);
      }
      */
      
   }
}