class template

<queue>

FIFO queue

empty

size

front

back

push_back

pop_front

queue

s are a type of container adaptor, specifically designed to operate in a FIFO context (first-in first-out), where elements are inserted into one end of the container and extracted from the other.s are implemented as, which are classes that use an encapsulated object of a specific container class as its, providing a specific set of member functions to access its elements. Elements areinto theof the specific container andfrom itsThe underlying container may be one of the standard container class template or some other specifically designed container class. This underlying container shall support at least the following operations:The standard container classesandfulfill these requirements. By default, if no container class is specified for a particularclass instantiation, the standard containeris used.