Question

I am trying to get familiar with boost::geometry::point. In my class I have a default constructor with no parameters and I want to initialize in this case all point values with zero.

As the set/get functions are templates, the following code part would yield an error at compile time:

    for( std::size_t i = 0; i < pnt.size() ; i++ )
    {
        pnt.set<i>( 0.0 );
    }

To refer the documentation http://www.boost.org/doc/libs/1_51_0/libs/geometry/doc/html/geometry/reference/models/model_point.html

I need to set some values because:

Coordinates are not initialized. If the constructor with parameters is not called and points are not assigned using set or assign then the coordinate values will contain garbage.

Is there a way to initialize all values with zero at compile time? If not then at runtime?

Answer 1

You can use assign_zero or assign_values (this one only works for 2, 3 and 4 components):

boost::geometry::assign_zero(pnt);
boost::geometry::assign_values(pnt, 0.0, 0.0);

If you are using a custom point class you need to register it using one of the BOOST_GEOMETRY_REGISTER_POINT... in order to be able to use Boost Geometry functionality. You can find several examples here.