find_if (3C++std) - Tru64 UNIX
Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc. NAME
find_if - Find an occurrence of value in a sequence that satisfies a
specifed predicate.
SYNOPSIS
#include <algorithm>
template <class InputIterator, class Predicate>
InputIterator find_if(InputIterator first,
InputIterator last,
Predicate pred);
DESCRIPTION
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 first and last, 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 [first, last) for which the
following condition holds:
pred(*i) == true.
If no such iterator is found, find_if returns last.
COMPLEXITY
find_if performs at most last-first applications of the corresponding
predicate.
EXAMPLE
//
// find.cpp
//
#include <vector>
#include <algorithm>
#include <iostream.h>
int main()
{
typedef vector<int>::iterator iterator;
int d1[10] = {0,1,2,2,3,4,2,2,6,7};
// Set up a vector
vector<int> v1(d1,d1 + 10);
// Try find
iterator it1 = find(v1.begin(),v1.end(),3);
// it1 = v1.begin() + 4;
// Try find_if
iterator it2 =
find_if(v1.begin(),v1.end(),bind1st(equal_to<int>(),3));
// it2 = v1.begin() + 4
// Try both adjacent_find variants
iterator it3 = adjacent_find(v1.begin(),v1.end());
// it3 = v1.begin() +2
iterator it4 =
adjacent_find(v1.begin(),v1.end(),equal_to<int>());
// v4 = v1.begin() + 2
// Output results
cout << *it1 << " " << *it2 << " " << *it3 << " "
<< *it4 << endl;
return 0;
}
Output : 3 3 2 2
WARNING
If your compiler does not support default template parameters then you need
to always supply the Allocator template argument. For instance you'll have
to write:
vector<int, allocator<int> >
instead of:
vector<int>
SEE ALSO
adjacent_find, Algorithms, find, find_end, find_first_of
STANDARDS CONFORMANCE
ANSI X3J16/ISO WG21 Joint C++ Committee
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