Re: Type Functors

I have this class:

class test {
public:
    int getpp()
    {
        return pp;
    }

    void setpp(int i) {
        pp = i;
    }

private:
    int pp;
};

Now I would like to insert it into a set:

std::set<test, std::less<test> > my_set;
test t1;
my_set.insert(t1);

This does not work (missing a '<' operator) so I add the following to test:

class test {
public:
    int getpp()
    {
        return pp;
    }

    void setpp(int i) {
        pp = i;
    }

      bool operator <(test const& t) const {

        return (*this).getpp() < t.getpp();
    }

private:
    int pp;
};

Which does not work either.

std::less implements something like:

bool operator() (T const& x, T const& y) const {
    return x < y;

}
So I don't quite see why I need to define '<' in 'test' when I supply
std::less<test> to my_set. It seems like double work.