Find the first mismatch between two sequences

Source code

Declaration

template <class InputIterator1, class InputIterator2>
pair<InputIterator1, InputIterator2> mismatch(InputIterator1 first1,
                                              InputIterator1 last1,
                                              InputIterator2 first2);

template <class InputIterator1, class InputIterator2, class BinaryPredicate>
pair<InputIterator1, InputIterator2> mismatch(InputIterator1 first1,
                                              InputIterator1 last1,
                                              InputIterator2 first2,
                                              BinaryPredicate binary_pred);

Description          For the sequence in the range [ first1, last1) and the sequence in the range beginning at first2 , each mismatch  function returns a pair   of iterators i and j referring to the first elements

and , respectively, such that and are different , or the pair of last1 and the location n locations past first2, where n is the size of the range [ first, last) , if no such difference  occurs. In the first function checks for element equality are made with operator==, while in the second they are made with the function object binary_pred.

Type requirements

• InputIterator1 and InputIterator2 must be at least input iterators .
• BinaryPredicate must be a function object type that provides int operator()(T1, T2), where T1 and T2 are the dereference types of InputIterator1 and InputIterator2, respectively.

Group Non-mutating sequence operations.

Time complexity Linear.

If a mismatch  is found, then the number of equality operations is the size of the range [ first1, i] ; otherwise, the number of equality operations is the size of the range [ first1, last1) .

Space complexity Constant.

Mutative? No.

Glossary terms BinaryPredicate, constant space, dereference type, function object, function object type, InputIterator, iterator, linear time, mutative, operator ==, pair, predicate, range, sequence.

Example Select here to view the source code for the example.

Implementation Select here to view source code (Copyright (C) 1994, Hewlett-Packard Company) for this algorithm.