C++ std::set custom comparator -

well, problem i'm using std::set custom comparator, like:

class { public:     a(int x, int y):         _x(x), _y(y)     {     }      int hashcode(){ return (_y << 16) | _x; }  private:     short int _y;     short int _x; };  struct comp {     bool operator() (a* g1, a* g2) const     {         return g1->hashcode() < g2->hashcode();     } }; 

so, use like

std::set<a*, comp> myset;  // insert data a* = new a(2,1); a* b = new a(1,3); myset.insert(a); myset.insert(b); 

now problem this:

myset.find( (2 << 16) | 1 ); 

but, of course, excepts a* not short int.

so, know use std::find_if, won't render useless custom comparator? iterate whole list, wouldn't it? there way use find hashcode rather object itself?

thank you!

set::find takes argument of type key_type (see discussion why set::find not template?). using std::set have construct temporary object use find.

myset.find(a(2, 1)); 

if not cheap construct might want use std::map<int, a> (or wrapper around it) instead.