std::reverse_copy

template <class BidirectionalIterator, class OutputIterator>  OutputIterator reverse_copy (BidirectionalIterator first,                               BidirectionalIterator last, OutputIterator result);

Copy range reversed

Copies the elements in the range [first,last) to the range beginning at result, but in reverse order.

此函数模板的行为等同于

template <class BidirectionalIterator, class OutputIterator>
  OutputIterator reverse_copy (BidirectionalIterator first,
                               BidirectionalIterator last, OutputIterator result)
{
  while (first!=last) {
    --last;
    *result = *last;
    ++result;
  }
  return result;
}

参数

first, last: Bidirectional iterators to the initial and final positions of the sequence to be copied. The range used is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
result: Output iterator to the initial position of the range where the reversed range is stored.
The pointed type shall support being assigned the value of an element in the range [first,last).

这些范围不应重叠。

返回值

An output iterator pointing to the end of the copied range, which contains the same elements in reverse order.

示例

// reverse_copy example
#include <iostream>     // std::cout
#include <algorithm>    // std::reverse_copy
#include <vector>       // std::vector

int main () {
  int myints[] ={1,2,3,4,5,6,7,8,9};
  std::vector<int> myvector;

  myvector.resize(9);    // allocate space

  std::reverse_copy (myints, myints+9, myvector.begin());

  // print out content:
  std::cout << "myvector contains:";
  for (std::vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)
    std::cout << ' ' << *it;

  std::cout << '\n';

  return 0;
}

输出

myvector contains: 9 8 7 6 5 4 3 2 1

复杂度

Linear in the distance between first and last: Performs an assignment for each element.

数据竞争

访问范围 [first,last) 中的对象。
修改 result 和返回的迭代器之间的范围内的对象。
Each object is accessed exactly once.

异常

Throws if either an element assignment or an operation on an iterator throws.
请注意，无效参数会导致未定义行为。

另见

reverse: 反转范围（函数模板）

rotate_copy: 复制向左旋转后的范围（函数模板）

copy: 复制元素范围（函数模板）

copy_backward: 向后复制元素范围（函数模板）

swap: 交换两个对象的值（函数模板）