cppChange4DigitNum

#include <iostream>

int main()
{
    const int max3digit{ 999 };
    const int min5digit{ 10000 };

    // enum Pos is like four constants packed together under one roof
    // It simply replaces
    // const int one {1};
    // const int two {10};
    // const int three {100};
    // const int four {1000};

    enum Pos { one = 1, two = 10, three = 100, four = 1000 };

    int num{ 1234 };
    int res{ 0 };

    std::cout << "Enter four digit number\n";
    std::cin >> num;

    if (num > max3digit and num < min5digit)
    {
        res += (num % 10) * Pos::two;
        num /= 10;
        res += (num % 10) * Pos::one;
        num /= 10;
        res += (num % 10) * Pos::four;
        num /= 10;
        res += (num % 10) * Pos::three;

        std::cout << "Changed digits: " << res << '\n';
    }
    else
    {
        std::cout << "Not a four digit number!\n";
    }

    return 0;
}