1 package com.java.test; 2 3 import java.util.Scanner; 4 5 public class practice3_09 { 6 7 public static void main(String[] args) { 8 Scanner sc = new Scanner(System.in); 9 System.out.print("Enter the first 9 digits of an ISBN as integer:"); 10 String s = sc.nextLine(); 11 //char[] arr =s.toCharArray(); 12 int[] num = new int[s.length()]; 13 for (int i = 0; i < num.length; i++) { 14 num[i] = (int)s.charAt(i) - '0'; 15 } 16 int sum = 0; 17 for (int i = 0; i < num.length; i++) { 18 sum += (i + 1)*num[i]; 19 } 20 int d = sum % 11; 21 if(d == 10) { 22 System.out.println(s + "X"); 23 } else { 24 System.out.println(s + d); 25 } 26 } 27 28 }