front

Description

Returns the first element in the sequence.

Synopsis

template <typename Sequence>
typename result_of::front<Sequence>::type
front(Sequence& seq);

template <typename Sequence>
typename result_of::front<Sequence const>::type
front(Sequence const& seq);

Parameters

Parameter	Requirement	Description
`seq`	Model of Forward Sequence	The sequence we wish to investigate.

Expression Semantics

front(seq);

Return type: Returns a reference to the first element in the sequence seq if seq is mutable and e = o, where e is the first element in the sequence, is a valid expression. Else, returns a type convertable to the first element in the sequence.

Precondition: empty(seq) == false

Semantics: Returns the first element in the sequence.

Header

#include <boost/fusion/sequence/intrinsic/front.hpp>
#include <boost/fusion/include/front.hpp>

Example

vector<int, int, int> v(1, 2, 3);
assert(front(v) == 1);