find_if

_First

An input iterator addressing the position of the first element in the range to be searched.

_Last

An input iterator addressing the position one past the final element in the range to be searched.

_Pred

User-defined predicate function object that defines the condition to be satisfied by the element being searched for. A predicate takes single argument and returns true or false.

An input iterator that addresses the first element in the range that satisfies the condition specified by the predicate.

This template function is a generalization of the algorithm find, replacing the predicate "equals a specific value" with any predicate.

// alg_find_if.cpp
// compile with: /EHsc
#include <list>
#include <algorithm>
#include <iostream>

bool greater10 ( int value )
{
   return value >10;
}

int main( )
{
   using namespace std;

   list <int> L;
   list <int>::iterator Iter;
   list <int>::iterator result;
   
   L.push_back( 5 );
   L.push_back( 10 );
   L.push_back( 15 );
   L.push_back( 20 );
   L.push_back( 10 );

   cout << "L = ( " ;
   for ( Iter = L.begin( ) ; Iter != L.end( ) ; Iter++ )
      cout << *Iter << " ";
   cout << ")" << endl;

   
   result = find_if( L.begin( ), L.end( ), &greater10 );
   if ( result == L.end( ) )
      cout << "There is no element greater than 10 in list L."
           << endl;
   else
   {
      result++;
      cout << "There is an element greater than 10 in list L,"
           << "\n and it is followed by a "
           <<  *(result) << "." << endl;
   }
}

L = ( 5 10 15 20 10 )
There is an element greater than 10 in list L,
 and it is followed by a 20.

Header: <algorithm>

Namespace: std

Reference