Return an input iterator positioned at the first element in the range [ first , last ) that causes pred to return true . If no such element exists, return last .

Declaration


  
#include <algorithm>

template< class InputIterator, class Predicate >
InputIterator find_if
  (
  InputIterator first,
  InputIterator last,
  Predicate pred
  );

Complexity

Time complexity is linear, as a maximum of ( last - first ) comparisons are performed. Space complexity is constant.

Example <ospace/osstd/examples/findif0.cpp>


    #include <iostream>
#include <algorithm>

int numbers[ 6 ] = { 2, 4, 8, 15, 32, 64 };

bool
odd( int a_ )
  {
  return a_ % 2;
  }

void
main()
  {
  int* location = find_if( numbers, numbers + 6, odd );

  if ( location != numbers + 6 )
    cout
      << "Value "
      << *location
      << " at offset "
      << ( location - numbers )
      << " is odd"
      << "\n";
  }


Value 15 at offset 3 is odd

Example <ospace/osstd/examples/findif1.cpp>


    #include <iostream>
#include <algorithm>
#include <vector>

bool
div_3( int a_ )
  {
  return a_ % 3 ? 0 : 1;
  }

void
main()
  {
  vector< int > v ( 10 );
  for ( size_t i = 0; i < v.size(); ++i )
    v[ i ] =( i + 1 ) *( i + 1 );
  vector< int > ::iterator iter;

  iter = find_if( v.begin(), v.end(), div_3 );

  if ( iter != v.end() )
    cout
       << "Value "
       << *iter
       << " at offset "
       << ( iter - v.begin() )
       << " is divisible by 3"
       << "\n";
  }

Value 9 at offset 2 is divisible by 3

find_if

Library

Declaration

Complexity

Example <ospace/osstd/examples/findif0.cpp>

Example <ospace/osstd/examples/findif1.cpp>