adjacent_find(3C++)

Standard C++ Library
Copyright 1998, Rogue Wave Software, Inc.

NAME

adjacent_find

- Find the first adjacent pair of elements in a sequence that are equivalent.

SYNOPSIS

#include <algorithm>
template <class ForwardIterator>

ForwardIterator
adjacent_find(ForwardIterator first,

ForwardIterator last);

template <class ForwardIterator, class BinaryPredicate>
ForwardIterator

adjacent_find(ForwardIterator first, ForwardIterator last,

BinaryPredicate pred);

DESCRIPTION

There are two versions of the adjacent_find algorithm. The first finds equal adjacent elements in the sequence defined by iterators first and last and returns an iterator i pointing to the first of the equal elements. The second version lets you specify your own binary function to test for a condition. It returns an iterator i pointing to the first of the pair of elements that meet the conditions of the binary function. In other words, adjacent_find returns the first iterator i such that both i and i + 1 are in the range [first, last) for which one of the following conditions holds:

∗i == ∗(i + 1)

or

pred(∗i,∗(i + 1)) == true

If adjacent_find does not find a match, it returns last.

COMPLEXITY

adjacent_find performs exactly find(first,last,value) - first applications of the corresponding predicate.

EXAMPLE

//
// find.cpp
//
#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;

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);

// Try find_if

iterator it2 =

find_if(v1.begin(),v1.end(),bind1st(equal_to<int>(),3));

// Try both adjacent_find variants

iterator it3 = adjacent_find(v1.begin(),v1.end());

iterator it4 =

adjacent_find(v1.begin(),v1.end(),equal_to<int>());

// Output results

cout << ∗it1 << " " << ∗it2 << " " << ∗it3 << " "

<< ∗it4 << endl;

return 0;

}

Program Output :

3 3 2 2

WARNINGS

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

vector<int,allocator<int> >

instead of:

vector<int>

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

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