C++: What is the difference between map and unordered_map?

1#include <map>
2
3std::map<int, std::string> m;
4m[3] = "three";
5m[1] = "one";
6m[2] = "two";
7
8// Sorted: 1, 2, 3
9for (const auto& [key, value] : m) {
10    std::cout << key << ": " << value << "\n";
11}

1#include <unordered_map>
2
3std::unordered_map<int, std::string> um;
4um[3] = "three";
5um[1] = "one";
6um[2] = "two";
7
8// Unordered: 3, 1, 2 (or any order)
9for (const auto& [key, value] : um) {
10    std::cout << key << ": " << value << "\n";
11}