< cpp‎ | algorithm
Algorithm library
Constrained algorithms and algorithms on ranges (C++20)
Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
Execution policies (C++17)
Non-modifying sequence operations
Batch operations
Search operations
(C++11)                (C++11)(C++11)

Modifying sequence operations
Copy operations
Swap operations
Transformation operations
Generation operations
Removing operations
Order-changing operations
(until C++17)(C++11)
Sampling operations

Sorting and related operations
Partitioning operations
Sorting operations
Binary search operations (on partitioned ranges)
Set operations (on sorted ranges)
Merge operations (on sorted ranges)
Heap operations
Minimum/maximum operations
Lexicographical comparison operations
Permutation operations
C library

Numeric operations
Operations on uninitialized memory
Defined in header <algorithm>
template< class BidirIt1, class BidirIt2 >
BidirIt2 move_backward( BidirIt1 first, BidirIt1 last, BidirIt2 d_last );
(since C++11)
(until C++20)
template< class BidirIt1, class BidirIt2 >
constexpr BidirIt2 move_backward( BidirIt1 first, BidirIt1 last, BidirIt2 d_last );
(since C++20)

Moves the elements from the range [firstlast), to another range ending at d_last. The elements are moved in reverse order (the last element is moved first), but their relative order is preserved.

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


[edit] Parameters

first, last - the range of the elements to move
d_last - end of the destination range
Type requirements
BidirIt1, BidirIt2 must meet the requirements of LegacyBidirectionalIterator.

[edit] Return value

Iterator in the destination range, pointing at the last element moved.

[edit] Complexity

Exactly last - first move assignments.

[edit] Possible implementation

template<class BidirIt1, class BidirIt2>
BidirIt2 move_backward(BidirIt1 first, BidirIt1 last,
                       BidirIt2 d_last)
    while (first != last)
        *(--d_last) = std::move(*(--last));
    return d_last;

[edit] Notes

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

[edit] Example

#include <algorithm>
#include <iostream>
#include <iterator>
#include <string>
#include <string_view>
#include <vector>
using container = std::vector<std::string>;
void print(std::string_view comment, const container& src, const container& dst = {})
    auto prn = [](std::string_view name, const container& cont)
        std::cout << name;
        for (const auto &s : cont)
            std::cout << (s.empty() ? "∙" : << ' ';
        std::cout << '\n';
    std::cout << comment << '\n';
    prn("src: ", src);
    if (dst.empty())
    prn("dst: ", dst);
int main()
    container src {"foo", "bar", "baz"};
    container dst {"qux", "quux", "quuz", "corge"};
    print("Non-overlapping case; before move_backward:", src, dst);
    std::move_backward(src.begin(), src.end(), dst.end());
    print("After:", src, dst);
    src = {"snap", "crackle", "pop", "lock", "drop"};
    print("Overlapping case; before move_backward:", src);
    std::move_backward(src.begin(), std::next(src.begin(), 3), src.end());
    print("After:", src);


Non-overlapping case; before move_backward:
src: foo bar baz
dst: qux quux quuz corge
src: ∙ ∙ ∙
dst: qux foo bar baz
Overlapping case; before move_backward:
src: snap crackle pop lock drop
src: ∙ ∙ snap crackle pop

[edit] See also

moves a range of elements to a new location
(function template) [edit]
moves a range of elements to a new location in backwards order