(Business: check ISBN-13) ISBN-13 is a new standard for identifying books. It uses 13 digits:d1d2d3d4d5d6d7d8d9d10d11d12d13

import java.util.Scanner;
public class Main
{
	public static void main(String[] args) {
	    Scanner input=new Scanner(System.in);
	    System.out.println("please enter the first 12 digits of an ISBN-13 as a string : ");
	    String isbn=input.next();
	    System.out.println((int)isbn.charAt(3)+(int)isbn.charAt(2));
	    int checksum= 10-((int)isbn.charAt(0)+3*isbn.charAt(1)+isbn.charAt(2)+3*isbn.charAt(3)+isbn.charAt(4)+3*isbn.charAt(5)+isbn.charAt(6)+3*isbn.charAt(7)+isbn.charAt(8)+3*isbn.charAt(9)+isbn.charAt(10)+3*isbn.charAt(11)%10);
	    if(checksum==10)
	    checksum=0;
	    System.out.println("checksum="+checksum);
	    isbn=isbn+checksum;
	    System.out.println("the standard ISBN-13 IS : "+isbn);
	}
}