std::unordered_set::cbegin

// unordered_set::cbegin/cend example
#include <iostream>
#include <string>
#include <unordered_set>
int main ()
{
  std::unordered_set<std::string> myset =
  {"Mercury","Venus","Earth","Mars","Jupiter","Saturn","Uranus","Neptune"};
  std::cout << "myset contains:";
  for ( auto it = myset.cbegin(); it != myset.cend(); ++it )
    std::cout << " " << *it;    // cannot modify *it
  std::cout << std::endl;
  std::cout << "myset's buckets contain:\n";
  for ( unsigned i = 0; i < myset.bucket_count(); ++i) {
    std::cout << "bucket #" << i << " contains:";
    for ( auto local_it = myset.cbegin(i); local_it!= myset.cend(i); ++local_it )
      std::cout << " " << *local_it;
    std::cout << std::endl;
  }
  return 0;
}