bind on member functions of stl containers

Hi,

I would like to accomplish

Code:

---

#include <tr1/functional>
#include <iostream>
#include <vector>
#include <set>
#include <algorithm>

using namespace std;
using namespace tr1;
using namespace placeholders;


int main()
{
        int ar[] = {0, 1, 2, 3, 4, 5};
        vector<int> ivec(ar, ar+6);
        set<int> iset(ar, ar+6);

        for_each(ivec.begin(), ivec.end(),
                        bind(&std::set<int>::erase, &iset, _1));

        cout << iset.size();

        return 0;
}

---

and I do not see why this piece of code does not compile...

The reason is (assuming there is this tr1/functional header with all the stuff, I used boost::lambda) that set::erase is an overloaded method. You can't deduce template arguments from an overloaded function unless you are more explicit.

(With boost) I did this:

Code:

---

set<int>::size_type( set<int>::*mp)(const int&) = &set<int>::erase;

        for_each(ivec.begin(), ivec.end(),
                        bind(mp, &iset, _1));

---

It should also work with a static cast of the function pointer.

As you can see it is rather verbous. Whether it pays off is up to you.

Thank you! I did not think about it and pointers to member functions are not trivial... I'll use this solution with a comment and a good name.

std::tr1::bind is equivalent to boost::bind, it allows to not depend on boost as it is now part of most C++ implementations. TR1 also has shared_ptr and ref, cref (and other things I am not using.)

Although, I'd recommend going for boost for now.
Not all compilers have TR1 implementations.
On the other hand, you can just use boost and it works everywhere.