'''
Barcode check digit checker.
The Barcode is explained here:
https://www.youtube.com/watch?v=e6aR1k-ympo
'''

def weighting(digit, weight):
    n=digit*weight
    return n


evenWeight=3
oddWeight=1
t=0

number=[0,5,1,0,0,0,0,1,2,5,1,7]  #This is a 12 digit bar code
l=(len(number))

for i in range (0, l-1,2):
        t=t+ weighting(number[i],evenWeight)
for i in range (1, l-1,2):
        t=t+weighting(number[i],oddWeight)


print(t)
remainder = t % 10
calcedCD= (10 - remainder) % 10
if number[l-1] == calcedCD:
    print("The calculated check digit and the last digit match!")
else:
    print("Oops! The calculated check digit doesn't match the last one read in.")