C++1y Automatic Type Deduction
The addition, err, redefinition of the auto keyword in C++11 was a great move to reduce code verbosity during the definition of local variables:
In addition to this convenient usage, employing auto in conjunction with the new (and initially weird) function-trailing-return-type syntax is useful for defining function templates that manipulate multiple parameterized types (see the third entry in the list of function definitions below).
In the upcoming C++14 standard, auto will also become useful for defining normal, run-of-the-mill, non-template functions. As the fourth entry below illustrates, we’ll be able to use auto in function definitions without having to use the funky function-trailing-return-type syntax (see the useless, but valid, second entry in the list).
For a more in depth treatment of C++11’s automatic type deduction capability, check out Herb Sutter’s masterful post on the new AAA (Almost Always Auto) idiom.