.\" ident @(#)find_if.3
.\" Standard Template Library
.\" $$RW_INSERT_HEADER "slyrs.man"
.TH find_if 3C++ "02 Apr 1998" "Rogue Wave Software" "-"
.ce2
Standard C++ Library   
Copyright 1998, Rogue Wave Software, Inc.   

.SH NAME

\f2find_if\fP

\ - Finds an occurrence of a value in a sequence that satisfies a specified predicate.



.SH  SYNOPSIS


.br
#include <algorithm>
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template <class InputIterator, class Predicate>
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InputIterator find_if(InputIterator first,
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InputIterator last,
.br
Predicate pred);



.SH  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 \f2first\fP and \f2last\fP, while the condition is defined by the third argument: a predicate function that returns a boolean value. find_if returns the first iterator \f2i\fP in the range \f2[first, last)\fP for which the following condition holds:

\f2pred(*i) == true.\fP

If no such iterator is found, find_if returns \f2last\fP.



.SH  COMPLEXITY


find_if performs at most \f2last-first\fP applications of the corresponding predicate.



.SH  EXAMPLE



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/
.br
// find.cpp
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//
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#include <vector>
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#include <algorithm>
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#include <functional>
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#include <iostream>
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using namespace std;
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int main()
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{
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typedef vector<int>::iterator iterator;
.br
int d1[10] = {0,1,2,2,3,4,2,2,6,7}; 
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// Set up a vector
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vector<int> v1(d1,d1 + 10);
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// Try find  
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iterator it1 = find(v1.begin(),v1.end(),3);
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// it1 = v1.begin() + 4;
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// Try find_if
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iterator it2 = 
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find_if(v1.begin(),v1.end(),bind1st(equal_to<int>(),3));
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// it2 = v1.begin() + 4
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// Try both adjacent_find variants
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iterator it3 = adjacent_find(v1.begin(),v1.end());
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// it3 = v1.begin() +2
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iterator it4 = 
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adjacent_find(v1.begin(),v1.end(),equal_to<int>());
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// v4 = v1.begin() + 2
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// Output results
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cout << *it1 << " " << *it2 << " " << *it3 << " " 
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<< *it4 << endl;
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return 0;
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}

.br
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Program Output



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.br
3 3 2 2



.SH  WARNINGS


If your compiler does not support default template parameters, then you always need to supply the \f2Allocator\fP template argument. For instance, you have to write:

\f2vector<int, allocator<int> >\fP

instead of:

\f2vector<int>\fP

If your compiler does not support namespaces, then you do not need the using declaration for \f2std\fP.



.SH  SEE ALSO


adjacent_find, Algorithms, find,_find_end, find_first_of