#include <iostream>
class A{
    public:
        void parse()
        {
            treatLine();
        };
        void treatLine()
        {
            std::cout << "treatLine in A" << std::endl;
        }
};

class B : public A{
    public:
        void treatLine()
        {
            std::cout << "treatLine in B" << std::endl;
        }
};

int main()
{
    B b;
    b.parse();
    return 0;
}

virtual void treatLine() {
    std::cout << "treatLine in A" << std::endl;
}