Question

I want to avoid code duplication as much as possible. Suppose I have a class such as,

class T {
    int val;
    bool operator < (const T& right) const { return val < right.val; }
}

I want to be able to call std::sort() like this,

std::sort( SomeContainer.begin(), SomeContainer.end(), FuncAdaptedFromOp );

This is my very first question in StackOverflow. Please be forgiving.

EDIT

The problem is that the class may have multiple bool T::Compare (const T& right) functions. I would still like an adapter. Take this example,

class Edge {
    Vertex u, v;
    bool CompareSrc (const Edge& right) const { return u < right.u; }
    bool CompareDest (const Edge& right) const { return v < right.v; }
}

Sometimes I want to sort by source Vertex and sometimes by destination Vertex. I just want to know if this is possible or not.

Answer 1

using namespace std::placeholders;
std::sort(SomeContainer.begin(), SomeContainer.end()
    // or use &Edge::CompareDest if you want that instead
    , std::bind(&Edge::CompareSrc, _1, _2) );

std::bind is C++11 though, so you may want to use boost::bind (in which case you shouldn’t use the preceding using directive) or the bind from TR1 if your implementation has that. Otherwise I’d advise you to handroll your own functor.