2. ISBN checksum (10 points). Write a program ISBNChecksum.java that takes a 9-digit int as a command-line argument and displays the checksum digit according to the following rules:

• Multiply the first digit by 10, the second by 9, the third by 8, and so on, down to the ninth digit by 2.
• Add the values together.
• Divide the sum by 11. What is the remainder?
• If the remainder is 0, the checksum is 0; otherwise, subtract the remainder from 11 to get the checksum digit.
• If the checksum that you come up with is 10, then X is used as the checksum digit!
• As an example, the checksum digit corresponding to 020131452 is 5 since 5 is the only value of x between 0 and 10 for which10*0 + 9*2 + 8*0 + 7*1 + 6*3 + 5*1 + 4*4 + 3*5 + 2*2 + 1*x is a multiple of 11.
• Hint 1: to extract the rightmost digit of a number use the modulus operator.
• Hint 2: to remove the rightmost digit of a number use the integer division by 10
• Hint 3: for full credit use a loop to compute the sum
• Assume the input value used to test your program is a 9-digit positive integer. Also assume that the input is a valid ISBN number without the checksum digit.

% java ISBNChecksum 313481157 X

% java ISBNChecksum 153296217 7