< cpp‎ | algorithm
Algorithm library
Execution policies (C++17)
Non-modifying sequence operations
Modifying sequence operations

Operations on uninitialized storage
Partitioning operations
Sorting operations
Binary search operations
Set operations (on sorted ranges)
Heap operations
Minimum/maximum operations

Numeric operations
C library
Defined in header <algorithm>
template< class BidirIt1, class BidirIt2 >
BidirIt2 copy_backward( BidirIt1 first, BidirIt1 last, BidirIt2 d_last );

Copies the elements from the range, defined by [first, last), to another range ending at d_last. The elements are copied in reverse order (the last element is copied first), but their relative order is preserved.

The behavior is undefined if d_last is within (first, last]. std::copy must be used instead of std::copy_backward in that case.


[edit] Parameters

first, last - the range of the elements to copy
d_last - end of the destination range..
Type requirements
BidirIt must meet the requirements of BidirectionalIterator.

[edit] Return value

iterator to the last element copied.

[edit] Complexity

Exactly last - first assignments.

[edit] Notes

When copying overlapping ranges, std::copy is appropriate when copying to the left (beginning of the destination range is outside the source range) while std::copy_backward is appropriate when copying to the right (end of the destination range is outside the source range).

[edit] Possible implementation

template< class BidirIt1, class BidirIt2 >
BidirIt2 copy_backward(BidirIt1 first, BidirIt1 last, BidirIt2 d_last)
    while (first != last) {
        *(--d_last) = *(--last);
    return d_last;

[edit] Example

#include <algorithm>
#include <iostream>
#include <vector>
int main()
    std::vector<int> from_vector;
    for (int i = 0; i < 10; i++) {
    std::vector<int> to_vector(15);
    std::copy_backward(from_vector.begin(), from_vector.end(), to_vector.end());
    std::cout << "to_vector contains: ";
    for (auto i: to_vector) {
        std::cout << i << " ";


to_vector contains: 0 0 0 0 0 0 1 2 3 4 5 6 7 8 9

[edit] See also

copies a range of elements to a new location
(function template) [edit]