Question

I use about 6 different C++ containers. I started writing print functions to output the container contents. Is this necessary? I would think this is part of the C++ library?

  void print_list(const list<int>& list_int)
    {
    for (list<int>::const_iterator it = list_int.begin(); it != list_int.end(); it++) cout << *it << " ";
    }
  void print_um(const unordered_map<int, double>& map_int_d)
    {
    for(unordered_map<int, double>::const_iterator it = map_int_d.begin(); it != map_int_d.end(); ++it)cout << "[" << it->first << "," << it->second << "] ";
    }

Answer 1

The code you give in your question has a hint as to why it is not part of the standard library. Your code uses square brackets and a comma with no spaces to show the pairs in the map. Other people may want it formatted differently so the options the standards committee had were:

1. Provide a lot of formatting options.
2. Provide no formatting options and make everyone who doesn’t like their formatting roll their own.
3. Do nothing and make everyone roll their own

They went with option three knowing that libraries would be developed that meet people’s specific needs.