#include <iostream>
#include <math.h>

using namespace std;

void CheckIfCodeValid( int siza);

int main()
{
    int Choice;


    while (1)
    {
        int ControlNumber = 0;
        long S = 0;
        int CNumber = 0;
        const short Size1 = 8;
        const short Size2 = 13;
        cout << "Menu" << endl;
        cout << "Wybierz rodzaj kodu kreskowego" << endl;
        cout << "\t1. EAN-8."
            << "\n\t2. EAN-13."
            << "\n\t9 By zakonczyc program"<<endl;
        cin >> Choice;
        switch (Choice)
        {
        case 1:
            char BarCode[13];
            cout << "Wprowadz swoj kod" << endl;
            cin >> BarCode;


            for (int i = 1; i < Size1; i++)
            {
                S += ((2 - pow(-1, i)) * BarCode[i - 1]);
            }
            ControlNumber = 10 - (S % 10);

            cout << BarCode[Size1-1] << endl;
            cout << S << endl;
            cout << ControlNumber << endl;
            CNumber = BarCode[Size1-1] - '0';
            cout << CNumber;
            if (ControlNumber == CNumber)
            {
                cout << "\n Valid bar code";
            }
            else
            {
                cout << "\n Invalid bar code";
                cout << "\n Valid Barcode is: " << endl;
                BarCode[7] = ControlNumber;
                for (int i = 0; i < 8; i++)
                {
                    cout << BarCode[i];
                }
            }

        case 2:
            //CheckIfCodeValid(13);
        case 9:
            exit(1);
        default:
            break;
        }
    }
}

void CheckIfCodeValid(int Size)
{


}