<commit_before>* Misc
** Items
*** get runtime type of a object
    #+begin_src c++
    #include <typeinfo>
    typeid(obj).name();
    #+end_src<commit_msg>add c++ reference usage<commit_after>* Misc
** Items
*** get runtime type of a object
    #+begin_src c++
    #include <typeinfo>
    typeid(obj).name();
    #+end_src
*** reference
    1. references much be initialed when declare
    2. references can't be rebound after initialization.
       #+begin_src C++ :includes <iostream>
       using namespace std;
       int a = 10;
       int c = 20;
       int& b = a;
       b=c;
       cout<<b;
       #+end_src

       #+RESULTS:
       : 20
{'fraction_non_alphanumeric': 0.12788906009244994, 'fraction_numerical': 0.012326656394453005, 'mean_word_length': 2.3678756476683938, 'pattern_counts': {'":': 0, '<': 8, '<?xml version=': 0, '>': 6, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
{'dir': 'git-commits-cleaned', 'id': '2084068', 'n_tokens_mistral': 225, 'n_tokens_neox': 212, 'n_words': 68}