On Jan 26, 2005, at 7:21 PM, Chris Goller wrote:
I have a struct that contains two values.
struct box { double width; double length; }
vector<box> boxes;
I want to accumlate all the widths of the boxes. The only solution I've found is to create a member function get_width that will return the width for use in mem_fun_ref
eg:
accumulate(make_transform_iterator(boxes.begin(), mem_fun_ref(&boxes::get_width)), make_transform_iterator(boxes.end(), mem_fun_ref(&boxes::get_width)), 0.0, plus<double>()));
Is there a boost way of not using mem_fun_ref, but rather returns the public member variable. Something that could be named mem_var_ref that would look like this:
accumulate(make_transform_iterator(boxes.begin(), mem_var_ref(&boxes::width)), make_transform_iterator(boxes.end(), mem_fun_ref(&boxes::width)), 0.0, plus<double>()));
This way I wouldn't need to add extra get logic to a structure that doesn't really need it othewise.
You can use boost::mem_fn(&boxes::width). Doug