Structured binding to access multiple return values

In C++ quite often you may want to return multiple values from a function and access it afterward. Here are few options for how things were done before C++ 17 structured binding was introduced.

Let's say we have a function like this that returns three values.

std::tuple<std::string, int, double> getDataPosition(){
	// some code returning multiple values
	return {"NQ", 100, 4455.98};
}

For accessing the data you can access it using std::tuple and std::get

std::tuple<std::string, int, double> positionData = getDataPosition(); // or auto..

std::string symbol = std::get<0>(positionData);
int volume = std::get<1>(positionData);
double price = std::get<2>(positionData);

It is quite messy and there was a better way using std::tie

std::string symbol;
int volume;
double price;

std::tie(symbol, volume,  price) = getDataPosition()

Notice you have to declare variable types in advance, not in the std:tie. From C++ 17 we can access it directly in one line using structured binding.

auto[symbol, volume, price] = getDataPosition();

This is way cleaner. The compiler does all its unpacking and figuring the types. Notice that you cannot declare variable types in advance. This will not work.

std::string symbol;
int volume;
double price;

auto[symbol, volume, price] = getDataPosition();