Library: Algorithms
Function
Algorithm that finds an occurrence of a value in a sequence that satisfies a specified predicate
#include <algorithm> namespace std { template <class InputIterator, class Predicate> InputIterator find_if(InputIterator start, InputIterator finish, Predicate pred); }
The find_if() algorithm allows you to search for the first element in a sequence that satisfies a particular condition. The sequence is defined by iterators start and finish, while the condition is defined by the third argument: a predicate function that returns a boolean value. find_if() returns the first iterator i in the range [start, finish) for which the following condition holds:
pred(*i) == true.
If no such iterator is found, find_if() returns finish.
find_if() performs at most finish-start applications of the corresponding predicate.
// // find.cpp // #include <vector> // for vector #include <algorithm> // for adjacent_find, find #include <functional> // for bind1st, equal_to #include <iostream> // for cout, endl int main () { // Typedef for convenience. typedef std::vector<int, std::allocator<int> > Vector; const Vector::value_type arr[] = { 0, 1, 2, 2, 3, 4, 2, 2, 6, 7 }; // Set up a vector. const Vector v1 (arr, arr + sizeof arr / sizeof *arr); // Try find. Vector::const_iterator it = std::find (v1.begin (), v1.end (), 3); std::cout << *it << ' '; // Try find_if. it = std::find_if (v1.begin (), v1.end (), std::bind1st (std::equal_to<Vector::value_type>(), 3)); std::cout << *it << ' '; // Try both adjacent_find variants. it = std::adjacent_find (v1.begin (), v1.end ()); std::cout << *it << ' '; it = std::adjacent_find (v1.begin (), v1.end (), std::equal_to<Vector::value_type>()); std::cout << *it << std::endl; return 0; } Program Output:
3 3 2 2
adjacent_find(), Algorithms, find(), find_end(), find_first_of()
ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 25.1.2