change4DigitNumMega

#include <iostream>

int main()
{
    int num{ 1234567890 };
    int newNum{ 0};
    int mul{ 1 };
    bool operation{true};

    /*while (num)
    {
        int digit{ (num % 10) * mul };

        newNum += (operation  ? digit * 10 :  digit / 10);
        num /= 10;
        mul *= 10;

        operation = !operation;
    }
*/

    //for (mul = 1, operation = true; num; num /= 10, mul *= 10, operation = !operation)
    //{
    //  int digit{ (num % 10) * mul };

    //  newNum += (operation ? digit * 10 : digit / 10);
    //}

    int digit{ 0 };
    for (mul = 1, operation = true; digit = ((num % 10) * mul), num; newNum += (operation ? digit * 10 : digit / 10), num /= 10, mul *= 10, operation = !operation);

    std::cout << newNum << '\n';
}