# Coin Change Exercise Program

import random

#greeting and instructions
print('The purpose of this exercise is to enter a number of coin values')
print('that add up to a displayed target value. \n')
print('Enter coins values as 1-penny, 5-nickel, 10-dime and 25-quarter')
print('Hit return after the last entered coin value.')
print('------------------')

#initializing variables
terminate = False
empty_str = ''

#start game sequence
while not terminate:
    amount = random.randint(1,99)
    print('Enter coins that at up to', amount, 'cents, one per line.\n')
    game_over = False
    total = 0

    while not game_over:
        valid_entry = False

        while not valid_entry:
            if total == 0:
                entry = input('Enter first coin: ')
            else:
                entry = input('Enter next coin: ')

            if entry in (empty_str, '1', '5', '10', '25'):
                valid_entry = True
            else:
                print('Invalid Entry')
        if entry == empty_str:
            if total == amount:
                print('Correct!')
            else:
                print('Sorry - you only entered', total, 'cents.')

            game_over = True
        else:
            total = total + int(entry)
            if total > amount:
                print('Sorry - total amount exceeds', amount, 'cents.')
                game_over = True

        if game_over:
            entry = input('\n Try again (y/n)?: ')

            if entry == 'n':
                terminate = True
print('Thank you for playing... goodbye')