C++17 STL Cookbook

How it works...

Structured bindings are always applied with the same pattern:

auto [var1, var2, ...] = <pair, tuple, struct, or array expression>;

• The list of variables var1, var2, ... must exactly match the number of variables contained by the expression being assigned from.
• The <pair, tuple, struct, or array expression> must be one of the following:
  • An std::pair.
  • An std::tuple.
  • A struct. All members must be non-static and defined in the same base class. The first declared member is assigned to the first variable, the second member to the second variable, and so on.
  • An array of fixed size.
• The type can be auto, const auto, const auto&, and even auto&&.

Not only for the sake of performance, always make sure to minimize needless copies ...