count

Returns the number of elements of a given type within a sequence.

template<
    typename Sequence,
    typename T
    >
typename result_of::count<Sequence, T>::type count(
    Sequence const& seq, T const& t);

Table 1.43. Parameters

Parameter	Requirement	Description
`seq`	A model of Forward Sequence, `e == t` must be a valid expression, convertible to `bool`, for each element `e` in `seq`	The sequence to search
`T`	Any type	The type to count

count(seq, t);

Return type: int

Semantics: Returns the number of elements of type T and equal to t in seq.

Linear. At most result_of::size<Sequence>::value comparisons.

#include <boost/fusion/algorithm/query/count.hpp>

const vector<double,int,int> vec(1.0,2,3);
assert(count(vec,2) == 1);