#
# Demonstrate catching exceptions in Python
#

#
#  Read a floating-point value from the user in a safe manner, looping back
#  to read another value if something non-numeric was entered.
#
#  Parameters:
#    prompt: The prompt to display before reading the value (defaults to the
#            empty string).
#
#  Returns: A floating-point value read from the user.
#
def safeInput(prompt = ""):
  # The input is not valid until a valid value is entered
  valid_input = False

  # Loop until a valid value is entered.
  while valid_input == False:
    try:
      # Read the value from the user.
      num = float(input(prompt))

      # Mark that a valid value was read successfully.
      valid_input = True

    except ValueError:
      # Report that the input was not valid.
      print("That wasn't numeric... Try again...")

  # Return the value entered by the user.
  return num

#
# Read two values safely.
#
a = safeInput("Enter a number: ")
b = safeInput("Enter another number: ")

#
# Demonstrate how a division by zero error can be caught.
#
try:
  print(a, "+", b, "=", a + b)
  print(a, "-", b, "=", a - b)
  print(a, "*", b, "=", a * b)
  print(a, "/", b, "=", a / b)
  print("Something else...")

except ZeroDivisionError:
  print(a, "/", b, "couldn't be performed because the denoninator is 0.")

except:
  print("Something went wrong...")
  quit()

#
# Show that the program continues to execute after the except blocks.
#
print("Here's the rest of the program...")