Chapter 4 Exercise 19, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

4.19 (Business: check ISBN-10) Rewrite the Programming Exercise 3.9 by entering the ISBN number as a string.

import java.util.Scanner;
 
public class ProgrammingEx4_19 {
 
 public static void main(String[] args) {
  Scanner input = new Scanner(System.in);
 
  System.out.print("Enter the first 9 digits of an ISBN as integer:");
  String isbn = input.next();
  //Ascii code for 0-9 is 48-57
  int d1 = (int)(isbn.charAt(0))-48;
  int d2 = (int)(isbn.charAt(1))-48;
  int d3 = (int)(isbn.charAt(2))-48;
  int d4 = (int)(isbn.charAt(3))-48;
  int d5 = (int)(isbn.charAt(4))-48;
  int d6 = (int)(isbn.charAt(5))-48;
  int d7 = (int)(isbn.charAt(6))-48;
  int d8 = (int)(isbn.charAt(7))-48;
  int d9 = (int)(isbn.charAt(8))-48;
 
  int d10 = (d1 * 1 + d2 * 2 + d3 * 3 + d4 * 4 + d5 * 5 + d6 * 6 + d7 * 7
    + d8 * 8 + d9 * 9) % 11;
 
  System.out.print("The ISBN-10 number is " + d1 + d2 + d3 + d4 + d5 + d6
    + d7 + d8 + d9);
 
  if (d10 == 10) {
   System.out.print('X');
  } else {
   System.out.print(d10);
  }
 
 }
 
}