RosettaCodeData/Task/ISBN13-check-digit/Java/isbn13-check-digit-2.java

19 lines
714 B
Java

public static void main(){
System.out.println(isISBN13("978-0596528126"));
System.out.println(isISBN13("978-0596528120"));
System.out.println(isISBN13("978-1788399081"));
System.out.println(isISBN13("978-1788399083"));
}
public static boolean isISBN13(String in){
int pre = Integer.parseInt(in.substring(0,3));
if (pre!=978)return false;
String postStr = in.substring(4);
if (postStr.length()!=10)return false;
int post = Integer.parseInt(postStr);
int sum = 38;
for(int x = 0; x<10;x+=2)
sum += (postStr.charAt(x)-48)*3 + ((postStr.charAt(x+1)-48));
if(sum%10==0) return true;
return false;
}