reverse


Category: algorithms	Component type: function

Prototype

template <class BidirectionalIterator>
void reverse(BidirectionalIterator first
BidirectionalIterator last);

Description

Reverse reverses a range. That is: for every i such that 0 <= i <= (last - first) / 2) it exchanges *(first + i) and *(last - (i + 1)).

Definition

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

Requirements on types

BidirectionalIterator is a model of Bidirectional Iterator.
BidirectionalIterator is mutable.

Preconditions

[first last) is a valid range.

Complexity

Linear: reverse(first last) makes (last - first) / 2 calls to swap.

Example

vector<int> V;
V.push_back(0);
V.push_back(1);
V.push_back(2);
copy(V.begin()
V.end()
ostream_iterator<int>(cout
" "));
                // Output: 0 1 2
reverse(V.begin()
V.end());
copy(V.begin()
V.end()
ostream_iterator<int>(cout
" "));
                // Output: 2 1 0