## Книга: Standard Template Library Programmer

Category: algorithms

Component type: function

### Prototype

template <class ForwardIterator>
template <class ForwardIterator, class BinaryPredicate>
ForwardIterator adjacent_find(ForwardIterator first, ForwardIterator last, BinaryPredicate binary_pred);

### Description

The first version of adjacent_find returns the first iterator i such that i and i+1 are both valid iterators in [first, last), and such that *i == *(i+1). It returns last if no such iterator exists.

The second version of adjacent_find returns the first iterator i such that i and i+1 are both valid iterators in [first, last), and such that binary_pred(*i, *(i+1)) is true. It returns last if no such iterator exists.

### Definition

Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.

### Requirements on types

For the first version:

• ForwardIterator is a model of Forward Iterator.

• ForwardIterator 's value type is Equality Comparable.

For the second version:

• ForwardIterator is a model of Forward Iterator.

• ForwardIterator's value type is convertible to BinaryPredicate's first argument type and to its second argument type.

### Preconditions

• [first, last) is a valid range.

### Complexity

Linear. If first == last then no comparison are performed; otherwise, at most (last – first) – 1 comparisons.

### Example

Find the first element that is greater than its successor.

int A[] = {1, 2, 3, 4, 6, 5, 7, 8};
const int N = sizeof(A) / sizeof(int);
const int* p = adjacent_find(A, A + N, greater <int>());
cout << "Element " << p – A << " is out of order: " << *p << " > " << *(p + 1) << "." << endl;