Structured bindings for unpacking bundled return values

custom structures— structured bindings.cpp

//Practice using structured bindings on custom structures.
#include <iostream>
#include <vector>
//Define & initialize data structures
struct employee {
	unsigned int id;
	std::string name;
	std::string role;
	unsigned salary;
} e1, e2, e3;

std::vector<employee> employees {
	e1, e2, e3/* Initialized from somewhere */
};
std::vector<std::string> init_names_of_employees (const std::vector<employee> employees) {
	std::vector<std::string> names_of_employees;
	for (const auto &[id, name, role, salary] : employees) {
	// If we don't use all of the binded variables, compiler will optimize it out and will not bind values to unused variables.
		names_of_employees.push_back(name);
	}
	return names_of_employees;
}
const std::vector<std::string> names_of_employees = init_names_of_employees(::employees);

void print_names (std::vector<std::string> names_of_employees) {
    for (const auto &name : names_of_employees) {
        std::cout << name << std::endl;
    }
}
//
//
//
//
int main() {
	//notice, we access global scope variable specifically
	init_names_of_employees (::employees);
    print_names(::names_of_employees);
}

std::map—structured bindings.cpp

#include <map>
std::map<std::string, size_t> animal_population {
	{"humans", 700000000000},
	{"chickens", 5802482509235849},
	{"camels", 97675678},
	"sheep", 742035748955},
	/* ... */
};
for (const auto &[species, count] : animal_population) {
	std::cout << "There are " << count << " " << species
		<< "on this planet.\n";

std::pair—structured bindings.cpp

//function prototype:
std::pair<int, int> divide_remainder (int dividend, int divisor);

//accessing the individual values of the result of a function with STRUCTURED BINDING
auto [fraction, remainder] = divide_remainder(16, 3);
std::cout << "16 / 3 is "
	<< fraction << " with a remainder of "
	<< remainder << '/n';
		  
// old way of accessing values of an std::pair
const auto result (divide_remainder(16, 3));
std::cout << "16 / 3 is "
	<< result.first << " with a remainder of "
	<< result.second << '/n';

std::tuple—structured bindings.cpp

//function prototype:
std::tuple<std::string, std::chrono::system_clock::time point, unsigned>
stock_info(const std::string &name);

//assigning using structured binding
const auto [name, valid_time, price = stock_info("INTC");