for_each - VC6

Funnily enough, boost::bind works:

for_each(V.begin(), V.end(), boost::bind(&B:rint,_1));
 

But im not sure how to use bind for calling a member function with a parameter, ie: (example stolen from some gamedev thread)

#include <vector>
#include <algorithm>
class C
{
public:
	void draw()
	{
		printf("draw");
	}
	void drawi(int i) {
		printf("d%d",i);
	}
};
typedef C* c_ptr;
int main()
{
	std::vector<c_ptr> v;
	for(int i=0; i<10; ++i)
		v.push_back(c_ptr(new C));
//this works:

	for_each(v.begin(), v.end(), boost::bind(&C::draw,_1));//this is wrong:

	int param=9;
	for_each(v.begin(), v.end(), boost::bind(&C::drawi,_1)(param));
}

can anyone tell me the correct usage for bind in this instance? thanks.

try something like this:

#include <iostream>
#include <vector>
#include <algorithm>

#include <boost/bind.hpp>

using namespace std;

class test
{
public:
    void draw()
    {
        cout << "draw()" << endl;
    }
    void draw(int i)
    {
        cout << "draw(" << i << ")" << endl;
    }
};

int main(int argc,char* argv[])
{
    typedef test* t_ptr;
    vector<t_ptr> v;
    for(int i = 0; i < 10; ++i)
        v.push_back(t_ptr(new test));
    
    for_each(v.begin(),v.end(),boost::bind(&test::draw,_1));
    int n = 9;
    for_each(v.begin(),v.end(),boost::bind(&test::draw,_1,n));
    return 0;
}

You want boost::bind(memberFunction, instance, _2) I believe.

The _2 is a special parameter that forces the template specialization for two function arguments to be used.

Well, sure you could do something like that.

if you do a:

functor = boost::bind(&a:rint,_1,_2)

You''d call it like this:

a* _a = new a;

functor(a,10);

However, if you did this:

functor = boost::bind(&a:rint,_1,10);

you''d call it like this:

functor(a);

and the functor will automagically supply the 10

Partial evaluation?! Way cool!

I always figured they''d be able to support it but didn''t know they already did. Say I have a function of n arguments and I supply two of them. Does the binder generate a function that needs n-2 arguments?

That would be correct

Check out the docs at boost.org, boost::bind is awesome.

Once Phoenix and BLL get integrated though, that''s gonna be one hell of a library.

Kool thanks daerid, that helped clear things up a bit
I would still be interested in finding out why the original code didn''t compile with VC6.. is it a compiler problem then?

Also, is there any good documentation on boost? I find the documentation that it comes with leaves a bit to be desired.

The only docs that I know of are at http://www.boost.org

I had to struggle along with them, as well as just test out all the different libraries a bunch of times before I wrapped my wits around ''em.