cpp17.structure.binding.org

Structure unbinding

from source code: https://skebanga.github.io/structured-bindings/

#include <iostream>
#include <tuple>
#include <string>
#include <vector>
#include <map>

struct MyTuple {
	int a; 
	std::string b;
	double c;
};

std::map<std::string, int> get_map()
{
    return
	    {
	        { "hello", 1 },
        	{ "world", 2 },
        	{ "it's",  3 },
        	{ "me",    4 },
	    };
}

int main()
{
	
	 auto tuple = std::make_tuple(1,"3",5.23);
	 int a;
	 std::string b; 
	 double c;
	 
	 std::tie ( a, b, c ) = tuple;	     
	 std::cout << a << " - " << b << " - " << c << std::endl;    
	 
	 // Same code with C++17 Syntax
	 
	 auto [d,e,f] = tuple ;	    
	 std::cout << d << " - " << e << " - " << f << std::endl;    
	 
	 //obtain references
	 auto& [g,h,j] = tuple ;     
	 g++;
	 
	 std::cout << g << " - " << h << " - " << j << std::endl;    
	 
	 // with structs    
	 MyTuple tp {10, "my tuple", 102.112};
	 auto [k,l,m] = tp;
	 
	 std::cout << k << " - " << l << " - " << m << std::endl;    
	 
	 MyTuple tp2 {11, "my tuple 2", 5.112};
	 std::vector<MyTuple> v {tp, tp2};
	 
	 for (const auto& [a, b, c] : v )
	 {
		 std::cout << a << " - " << b  << std::endl;    
	 }
	 
	 for (auto&& [ k, v ] : get_map())
	 {
		std::cout << "k=" << k << " v=" << v << '\n';
	 }
	 
	 return 0;	     
}