Question

Write a program in Python that asks the user for the ISBN of the book in the format xxx-x-xxx-xxxxx-x.

To validate:

1. Initialize a total to 0
2. Have the program remove the dashes so that only the 13 digits are left in the ISBN string
3. for each index of the first 12 digits in the 13 digit ISBN string
4. get the digit at the current index as an integer
5. If the current index is an even number, add the digit to the total otherwise add the digit times 3 to the total. So look at the index to determine what should be added to the total
6. After all digits are processed, the checksum will be 10 - ( total mod 10)
7. If the checksum is 10, make it 0.
8. If the checksum matches the last digit in the ISBN, the ISBN is valid, otherwise it is not. Display an appropriate message

Answer 1

Code

isbn=input("Enter ISBN in following format xxx-x-xxx-xxxxx-x: ")

total=0

isbnWithoutDash=""

for ch in isbn:
if ch.isdigit():
isbnWithoutDash+=ch

lastDigit=int(isbnWithoutDash[len(isbnWithoutDash)-1])

isbnWithoutDash=isbnWithoutDash[:-1]

for ch in isbnWithoutDash:
num=int(ch)
if(num%2==0):
total+=num
else:
total+=3*num

checksum=10-(total%10)

if checksum==10:
checksum=0
if checksum==lastDigit:
print("Valid")
else:
print("Invalid")

output

code snaps

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