Getting the answers to my homework :p
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
Style would be the great and best answer but you could add office decor
True, sites such as kickstarter and just giving are fantastic examples of such.