C++ auto& vs auto

Question

When creating local variables, is it correct to use (const) auto& or auto?

e.g.:

SomeClass object;
const auto result =          


        

Answer 1

Yes, it is correct to use auto and auto& for local variables. When getting the return type of a function, it is also correct to use auto&. This applies for range based for loops as well.

General rules for using auto are:

• Choose auto x when you want to work with copies.
• Choose auto &x when you want to work with original items and may modify them.
• Choose auto const &x when you want to work with original items and will not modify them.

You can read more about the auto specifier here.