Generate 13 bit barcode

13 Bit barcode rules ： The thirteenth digit is the check code calculated from the first twelve digits .

for example ：690123456789（ front 12 For random generation , Get the second 13 position ）

The process of calculating its check code is ：

@ The odd sum of the first twelve digits 6+0+2+4+6+8=26

@ The sum of the even digits of the first twelve 9+1+3+5+7+9=34

@ Add three times the sum of odd and even numbers 26+34*3=128

@ Take the single digit of the result ：128 The single digit of is 8

@ use 10 Subtract this single digit 10-8=2

So the check code is 2

（ notes ： If the single digit of the result is 0, Then the check code is not 10（10-0=10）, It is 0）

Implementation method ean13（） Calculate the verification code , Input 12 Bit bar code , Return the barcode with verification code .

example ： Input ：692223361219 Output ：6922233612192

The basic idea ：

Random generation 12 A digital , To store in the array . According to the requirements given in the title, find the 13 position , Put the obtained No 13 The bit check code is stored in the last bit of the array . Then print out the array .

Code ：

import java.util.Random;

public class Exer {
	public static void main(String[] args) {
		Random random = new Random();
		int[] arr = new int[13];// Define a length of 13 Array of 
		int oddSum = 0;// Odd digits and 
		int evenSum = 0;// Even digit sum 
		System.out.print(" Input 12 Bit barcode is ：");
		for(int i = 0; i < 12; i++) {
			arr[i] = random.nextInt(10);// Store the randomly generated number in the array 			
			System.out.print(arr[i]);
			if(i % 2 == 0) {
				oddSum += arr[i];				
			}else {
				evenSum += arr[i];				
			}
		}
		System.out.println();
		int sum = oddSum + evenSum * 3;// Add three times of odd and even sums 
		int ge = sum % 10;// The single digits of the result of adding odd sum and triple of even sum 
		System.out.print(" The returned barcode with verification code is ：");
		for(int i = 0; i < arr.length; i++) {
			if(ge == 0) {
				arr[arr.length] = 0;
			}else {
				arr[arr.length-1] = 10 - ge;
			}
			System.out.print(arr[i]);
		}
	}
}