What is the best way to use two keys with a std::map?

Question

I have a std::map that I\'m using to store values for x and y coordinates. My data is very sparse, so I don\'t want to use arrays or vectors, which would result in

Answer 1

Use std::pair for the key:

std::map, int> myMap;

myMap[std::make_pair(10,20)] = 25;
std::cout << myMap[std::make_pair(10,20)] << std::endl;