Searches for the first subsequence in a range that of a specified number of elements having a particular value or a relation to that value as specified by a binary predicate.

template<class ForwardIterator1, class Diff2, class Type>
ForwardIterator1 search_n(
ForwardIterator1 _First1,
ForwardIterator1 _Last1,
Size2 _Count,
const Type& _Val
);
template<class ForwardIterator1, class Size2, class Type, class BinaryPredicate>
ForwardIterator1 search_n(
ForwardIterator1 _First1,
ForwardIterator1 _Last1,
Size2 _Count,
const Type& _Val,
BinaryPredicate _Comp
);

Parameters

_First1

A forward iterator addressing the position of the first element in the range to be searched.

_Last1

A forward iterator addressing the position one past the final element in the range to be searched.

_Count

The size of the subsequence being searched for.

_Val

The value of the elements in the sequence being searched for.

_Comp

User-defined predicate function object that defines the condition to be satisfied if two elements are to be taken as equivalent. A binary predicate takes two arguments and returns true when satisfied and false when not satisfied.

Return Value

A forward iterator addressing the position of the first element of the first subsequence that matches the specified sequence or that is equivalent in a sense specified by a binary predicate.

Remarks

The operator== used to determine the match between an element and the specified value must impose an equivalence relation between its operands.

The range referenced must be valid; all pointers must be dereferenceable and within the sequence the last position is reachable from the first by incrementation.

Complexity is linear with respect to the size of the searched.

// alg_search_n.cpp
// compile with: /EHsc
#include <vector>
#include <list>
#include <algorithm>
#include <iostream>
// Return whether second element is twice the first
bool twice ( int elem1, int elem2 )
{
return 2 * elem1 == elem2;
}
int main( )
{
using namespace std;
vector <int> v1, v2;
vector <int>::iterator Iter1;
int i;
for ( i = 0 ; i <= 5 ; i++ )
{
v1.push_back( 5 * i );
}
for ( i = 0 ; i <= 2 ; i++ )
{
v1.push_back( 5 );
}
for ( i = 0 ; i <= 5 ; i++ )
{
v1.push_back( 5 * i );
}
for ( i = 0 ; i <= 2 ; i++ )
{
v1.push_back( 5 );
}
cout << "Vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
// Searching v1 for first match to (5 5 5) under identity
vector <int>::iterator result1;
result1 = search_n ( v1.begin( ), v1.end( ), 3, 5 );
if ( result1 == v1.end( ) )
cout << "There is no match for a sequence ( 5 5 5 ) in v1."
<< endl;
else
cout << "There is at least one match of a sequence ( 5 5 5 )"
<< "\n in v1 and the first one begins at "
<< "position "<< result1 - v1.begin( ) << "." << endl;
// Searching v1 for first match to (5 5 5) under twice
vector <int>::iterator result2;
result2 = search_n (v1.begin( ), v1.end( ), 3, 5 );
if ( result2 == v1.end( ) )
cout << "There is no match for a sequence ( 5 5 5 ) in v1"
<< " under the equivalence predicate twice." << endl;
else
cout << "There is a match of a sequence ( 5 5 5 ) "
<< "under the equivalence\n predicate twice"
<< "in v1 and the first one begins at "
<< "position "<< result1 - v1.begin( ) << "." << endl;
}

Vector v1 = ( 0 5 10 15 20 25 5 5 5 0 5 10 15 20 25 5 5 5 )
There is at least one match of a sequence ( 5 5 5 )
in v1 and the first one begins at position 6.
There is a match of a sequence ( 5 5 5 ) under the equivalence
predicate twicein v1 and the first one begins at position 6.