Difference between revisions of "cpp/algorithm/reverse"
From cppreference.com
(specified in terms of iter_swap in the standard (including C++14 bugfix from LWG issue 2039)) |
(rm argc, argv) |
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#include <algorithm> | #include <algorithm> | ||
| − | int main( | + | int main() |
{ | { | ||
std::vector<int> v({1,2,3}); | std::vector<int> v({1,2,3}); | ||
Revision as of 17:21, 12 September 2013
| Defined in header <algorithm>
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| template< class BidirIt > void reverse( BidirIt first, BidirIt last ); |
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Reverses the order of the elements in the range [first, last)
Behaves as if applying std::iter_swap to every pair of iterators first+i, (last-i) - 1 for each non-negative i < (last-first)/2
Contents |
Parameters
| first, last | - | the range of elements to reverse |
| Type requirements | ||
Return value
(none)
Possible implementation
template<class BidirIt> void reverse(BidirIt first, BidirIt last) { while ((first != last) && (first != --last)) { std::swap(*first++, *last); } } |
Example
Run this code
#include <vector> #include <iostream> #include <algorithm> int main() { std::vector<int> v({1,2,3}); std::reverse(std::begin(v), std::end(v)); std::cout << v[0] << v[1] << v[2] << '\n'; int a[] = {4, 5, 6, 7}; std::reverse(&a[0], &a[4]); std::cout << a[0] << a[1] << a[2] << a[3] << '\n'; }
Output:
321 7654
Complexity
linear in the distance between first and last
See also
| creates a copy of a range that is reversed (function template) |
