Initializing a static std::map<int, int> in C++
c++, stdmap, stl
Solution
Using C++11 initializer list {{},{},...}. The order of the initialized elements does not matter. The map will do the ordering by the key for you. If initializing unordered_map, it is the same principle where the sorted order will be determined by the hashing function and will appear to human eye as random:
#include <map>
using namespace std;
map<int, char> m = {{1, 'a'}, {3, 'b'}, {5, 'c'}, {7, 'd'}};
Using Boost.Assign:
#include <map>
#include "boost/assign.hpp"
using namespace std;
using namespace boost::assign;
map<int, char> m = map_list_of (1, 'a') (3, 'b') (5, 'c') (7, 'd');
Problem
What is the right way of initializing a static map? Do we need a static function that will initialize it?