queue class is used for the operations on a single ended queue.
A queue class is declared as:
template <class T, class Container = deque<T>> class queue
Constructor of queue:
explicit queue(const Container &x = Container( ));
Types of queue operators: ==, <, <=, !=, >, >=
Member functions of queue:
1) size() function: It is used to return the size of the queue.
2) empty( ) function: It returns true if queue is empty, otherwise false.
3) push( ) function: It is used to add an element at end of queue.
4) pop( ) function: It is used to remove first element in queue.
5) front( ) function: It is used to return a reference to the first element in the queue.
6) back( ) function: It is used to return a reference to the last element in the queue.