Re: [Boost-users] [iterator] transform_iterator

Subject: Re: [Boost-users] [iterator] transform_iterator
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2008-12-24 11:47:36

AMDG

Max wrote:
> I just came across transform_iterator and found it a useful generic tool.
> But is it possible for it to go further to make the following code get 
> compiled and run as expected?
>   

No.

> struct A
> {
> 	int i_;
> 	A() : i_(0) {}
> 	explicit A(int i) : i_(i) {}
> };
>
> const int N = 5;
> A a_list[N] = { A(-3), A(1), A(3), A(2), A(-4) }; 
>
> typedef boost::function<int(A)> fn_t;
>
> // sorting a_list according to the elements' i_ member
> std::stable_sort(boost::make_transform_iterator(a_list, fn_t(boost::bind(&A::i_, _1))),
> 	boost::make_transform_iterator(a_list+N, fn_t(boost::bind(&A::i_, _1))), 
> 	std::less<int>());
>   

stable_sort assumes that the sort keys are the same as the objects
that it is moving around.

In Christ,
Steven Watanabe