Defined in header <algorithm>

 

 

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

 

 

 

 

 

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

Parameters

first, last

-

the range of elements to reverse

Type requirements

-BidirIt must meet the requirements of BidirectionalIterator.

-The type of dereferenced BidirIt must meet the requirements ofSwappable.

Return value

(none)

Possible implementation



template<class BidirIt>
void reverse(BidirIt first, BidirIt last)
{
    while ((first != last) && (first != --last)) {
        std::iter_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';
}



注意reverse的第二个参数不是序列的最后一个元素的位置，而是此位置之后再向后一个，

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

例子中，reverse  反转长度4的int数组，第二参数是&a[4](最后一个元素a[3]的后一个)