On Thu, 20 Jul 2006, Tomas Rapkauskas wrote:

Hello, I am newbie using boost library. I have tried to use boost::minmax_element to calculate bounding box of 2D Points, but I failed...

Here is some code: struct S2DPoint { int x; int y; }; typedef std::vector<S2DPoint > Poly; Poly vect; ...

std::pair result = boost::minmax_element(poly.begin(), poly.end()); [snip]

I don't think you can compute the bounding box like that, essentially because boost::minmax_element returns a pair of iterators from the input range, one indicating the minimum, the other, the max. But in the case of a bounding box, only rarely the coordinates of both lower and higher bounds are points from the input set. What you need is something like std::for_each with a functor like this (uing your S2DPoint): struct update_min_max_points { S2DPoint ptMin ; S2DPoint ptMax ; update_min_max_points( const S2DPoint& first_pt ) : ptMin( first_pt ) , ptMax( first_pt ) { } void operator () ( const S2DPoint& pt ) const { if ( ptMin.x > pt.x ) { ptMin.x = pt.x ; } if ( ptMax.x < pt.x ) { ptMax.x = pt.x ; } if ( ptMin.y > pt.y ) { ptMin.y = pt.y ; } if ( ptMax.y < pt.y ) { ptMax.y = pt.y ; } } } ; And then you can use it like this: update_min_max_points result = std::for_each( poly.begin() + 1 , poly.end() , update_min_max_points( poly[ 0 ] ) ) ; And your result is in result.ptMin and result.ptMax. -- François Duranleau LIGUM, Université de Montréal "There are as many truths as there are people." - from _Neon Genesis Evangelion_