# 25 Algorithms library [algorithms]

## 25.2 Non-modifying sequence operations [alg.nonmodifying]

### 25.2.11 Equal [alg.equal]

``` template<class InputIterator1, class InputIterator2> bool equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2); template<class InputIterator1, class InputIterator2, class BinaryPredicate> bool equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, BinaryPredicate pred); template<class InputIterator1, class InputIterator2> bool equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2); template<class InputIterator1, class InputIterator2, class BinaryPredicate> bool equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, BinaryPredicate pred); ```

Remarks: If last2 was not given in the argument list, it denotes first2 + (last1 - first1) below.

Returns: If last1 - first1 != last2 - first2, return false. Otherwise return true if for every iterator i in the range [first1,last1) the following corresponding conditions hold: *i == *(first2 + (i - first1)), pred(*i, *(first2 + (i - first1))) != false. Otherwise, returns false.

Complexity: No applications of the corresponding predicate if InputIterator1 and InputIterator2 meet the requirements of random access iterators and last1 - first1 != last2 - first2. Otherwise, at most min(last1 - first1, last2 - first2) applications of the corresponding predicate.