Functions that need to return two values often return a pair . The type of the second element stored in the pair Model of Assignable Type requirements T1 and T2 must both be models of Assignable .
Additional operations have additional requirements.
Public base classes None. The assignment operator first pair See below. New members These members are not defined in the Assignable requirements, but are specific to pair . The type of the pair's first component. It uses constructs objects of types T1 and T2 using their default constructors.