The following code example is taken from the book
C++23 - The Complete Guide
by Nicolai M. Josuttis,
Leanpub, 2026
The code is licensed under a
Creative Commons Attribution 4.0 International License.
// raw code
#include <print>
#include <string>
#include <vector>
#include <deque>
#include <flat_map>
int main()
{
// define two associated containers:
std::deque<std::string> last{"Turner", "Bond", "Holmes"};
std::vector<std::string> first{"Tina", "James", "Sherlock"};
std::println("last: {}", last);
std::println("first: {}", first);
// initialize a flat map from two associated containers:
std::flat_map fm1{last, first}; // OK
std::println("fm1: {}", fm1);
std::flat_map<std::string, std::string, std::less<std::string>,
decltype(last), decltype(first)> fm2{last, first}; // OK
std::println("fm2: {}", fm2);
// declare a flat map for two associated containers:
std::flat_map<std::string, std::string, std::less<std::string>,
std::deque<std::string>, std::vector<std::string>> fm3;
//...
// assign values from two containers:
fm3 = decltype(fm3){last, first}; // OK
std::println("fm3: {}", fm3);
}