Answer:
In Java:
import java.util.*;
public class Main{
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
String isbn;
System.out.print("First 1:2 digits: ");
isbn = input.nextLine();
if(isbn.length()==12){
int chksum = 0;
for(int i = 0; i<12;i++){
if((i+1)%2==0){ chksum+= 3 * Character.getNumericValue(isbn.charAt(i)); }
else{ chksum+=Character.getNumericValue(isbn.charAt(i)); } }
chksum%=10;
chksum=10-chksum;
if(chksum==10){
System.out.print("The ISBN-13 number is "+isbn+"0");}
else{
System.out.print("The ISBN-13 number is "+isbn+""+chksum); } }
else{
System.out.print("Invalid Input");
} }}
Explanation:
See attachment for explanation where comments are used to explain each line
D. All of these
Reason being, they wouldn't have been made if something hasn't been discovered about them.
Possibly rephrase or rewrite the heading or whatever else you decide to repeat. You should never say the exact thing twice.
Hope I helped :)