std::reverse

 

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Template:ddcl list begin <tr class="t-dsc-header">

<td>

Defined in header <algorithm>

</td>

<td></td> <td></td> </tr> <tr class="t-dcl ">

<td class="t-dcl-nopad">

template< class BidirIt >
void reverse( BidirIt first, BidirIt last );

</td>

<td class="t-dcl-nopad"> </td> <td class="t-dcl-nopad"> </td> </tr> Template:ddcl list end

Reverses the order of the elements in the range [first, last).

Parameters

first, last	-	the range of elements to reverse
Type requirements
- BidirIt must meet the requirements of LegacyBidirectionalIterator.
- The type of dereferenced BidirIt must meet the requirements of Swappable.

Return value

(none)

Possible implementation

template<class BidirIt> void reverse(BidirIt first, BidirIt last) { for(;first<last;++first,--last) std::swap(*first,*last); }

Example

Run this code

#include <vector>
#include <iostream>
#include <algorithm>
 
int main(int argc, char** argv)
{
    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

Template:cpp/algorithm/dcl list reverse copy