"""
Exercise 1. 4 - Calculator
"""


#  Copyright (c) 2021. Pascal Syma. All rights reserved.

def calculator():
    """
    Calculator
    """
    choice = 0
    first = 0
    second = 0

    while True:
        try:
            print("""
1. Enter two integers
2. Add
3. Subtract
4. Multiply
5. Divide
0. Exit""")
            choice = int(input('Your choice: '))
            if choice > 5 or choice < 0:
                raise ValueError
        except ValueError:
            print('Input must be either 0,1,2,3,4 or 5.')
            continue

        if choice == 0:
            print('Exiting ... Goodbye !')
            return

        if choice == 1:
            try:
                first = int(input('Input first number : '))
                second = int(input('Input second number : '))
            except ValueError:
                print('Input must be an integer!')
                continue
        elif choice == 2:
            # Addition
            print(f'The result is {first + second}')
        elif choice == 3:
            # Subtraction
            print(f'The result is {first - second}')
        elif choice == 4:
            # Multiplication
            print(f'The result is {first * second}')
        elif choice == 5:
            # Division
            print(f'The result is {first // second}')


if __name__ == '__main__':
    calculator()