# search_n

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

*_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.

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.

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.

## Example

// alg_search_n.cpp // compile with: /EHsc #include <vector> #include <list> #include <algorithm> #include <iostream> // Return whether second element is 1/2 of the first bool one_half ( int elem1, int elem2 ) { return elem1 == 2 * 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( 10 ); } 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 one_half vector <int>::iterator result2; result2 = search_n (v1.begin( ), v1.end( ), 3, 5, one_half ); if ( result2 == v1.end( ) ) cout << "There is no match for a sequence ( 5 5 5 ) in v1" << " under the equivalence predicate one_half." << endl; else cout << "There is a match of a sequence ( 5 5 5 ) " << "under the equivalence\n predicate one_half " << "in v1 and the first one begins at " << "position "<< result2 - v1.begin( ) << "." << endl; }

## Requirements

Header: <algorithm>

Namespace: std