queue

Question 1

Element access

front( )

Answer 1

access the first element
Parameters
(none)

Return value
Reference to the first element.

Complexity
Constant

Question 2

Element access

back( )

Answer 2

access the last element
Parameters
(none)

Return value
reference to the last element

Complexity
Constant

Question 3

Capacity

empty( )

Answer 3

checks whether the underlying container is empty
Parameters
(none)

Return value
true if the underlying container is empty, false otherwise

Complexity
Constant

Question 4

Capacity

size( )

Answer 4

returns the number of elements
Parameters
(none)

Return value
The number of elements in the container.

Complexity
Constant.

Question 5

Modifiers

push( )

Answer 5

inserts element at the end
Parameters
value	-	the value of the element to push
Return value
(none)

Complexity
Equal to the complexity of Container::push_back.

Question 6

Modifiers

emplace( )

Answer 6

constructs element in-place at the end
Parameters
args - arguments to forward to the constructor of the element
Return value
(none) (until C++17)
The value or reference, if any, returned by the above call to Container::emplace_back. (since C++17)
Complexity
Identical to the complexity of Container::emplace_back.

Question 7

Modifiers

pop( )

Answer 7

removes the first element
Parameters
(none)

Return value
(none)

Complexity
Equal to the complexity of Container::pop_front.

Question 8

Modifiers

swap( )

Answer 8

swaps the contents
Parameters
other	-	container adaptor to exchange the contents with
Return value
(none)

Exceptions
noexcept specification:
noexcept(noexcept(swap(c, other.c)))
In the expression above, the identifier swap is looked up in the same manner as the one used by the C++17 std::is_nothrow_swappable trait.

(since C++11)
(until C++17)
noexcept specification:  
noexcept(std::is_nothrow_swappable_v)
(since C++17)
Complexity
Same as underlying container (typically constant).