Chapter 5, Problem 5.47PE

(Business: check ISBN-13) ISBN -13 is a new standard for identifying books. It uses 13 digits d₁d₂d₃d₄d₅d₆d₇d₈d₉d₁₀d₁₁d₁₂d₁₃. The last digit d₁₃ is a checksum, which is calculated from the other digits using the following formula:

10- (d₁ + 3d₂ + d₃ + 3d₄ + d₅ + 3d₆ + d₇ + 3d₈ + d₉ + 3d₁₀ + d₁₁ + 3d₁₂)%10

If the checksum is 10, replace it with 0. Your program should read the input as a string. Here are sample runs:

Enter the first 12 digits of an ISBN-13 as a string: 978013213080

The ISBN-13 number is 9780132130806

Enter the first 12 digits of an ISBN-13 as a string: 978013213079

The ISBN-13 number is 9780132130790

Enter the first 12 digits of an ISBN-13 as a string: 97801320

97801320 is an invalid input