public static int CalculateChecksum(string value)
{
var numbers = new GtinNumbers(value);
var sum = 3 * numbers.N1 +
numbers.N2 +
3 * numbers.N3 +
numbers.N4 +
3 * numbers.N5 +
numbers.N6 +
3 * numbers.N7 +
numbers.N8 +
3 * numbers.N9 +
numbers.N10 +
3 * numbers.N11 +
numbers.N12 +
3 * numbers.N13 +
numbers.N14 +
3 * numbers.N15 +
numbers.N16 +
3 * numbers.N17;
var checksum = sum.UpToNearestTen() - sum;
return(checksum);
}
public Gtin(string value) : base(value)
{
Numbers = new GtinNumbers(value);
}