pointer to member function

Question

I am trying to generalize the functions filterX() and filterY() in the following class Table to function filter().

Answer 1

A member function requires a pointer to the object instance. That is, think of getX as string Row::getX(const Table *this). You need to bind the member function with an instance placeholder.

E.g. using tr1,

vector vx = t.filter("x1", std::bind(&Row::getX, std::placeholders::_1));

The binding creates a functor that takes in a Row object, assuming that your filter function is correctly defined. You should show code for filter. I presume it should be:

template 
vector Table::filter(const string &s, function f)
{
    vector result;
    for (vector::const_iterator it = d_table.begin(), tEnd = d_table.end();
        it != tEnd; ++it)
    {
        if (s == f(*it)) result.push_back(it->getVal());
    }
    return result;
}