begin iterator of map not working c++ -

we have map:

std::map<double, colorref> colorset; 

here provide part of function returns colorref value

colorref getcolour(double value) const {    ...    for(std::map<double, colorref>::iterator ii=colorset.begin(); ii!=colorset.end(); ++ii)    {     std::cout << (*ii).first << ": " << (*ii).second << std::endl;    }    ...    return defaultcolor; } 

but, compiler gives error telling nonexistance of converting tree_const_iteratortotree_iterator in colorset.begin().

if delete const term function ok, must declare function const.

why error appearing? or can provide alternate way iterate though map?

use const_iterator:

   for(std::map<double, colorref>::const_iterator ii=colorset.begin(); ii!=colorset.end(); ++ii) 

ps

i use ii->first etc