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      std::ranges::swap_ranges,std::ranges::swap_ranges_result

      From cppreference.com
      <cpp‎ |algorithm‎ |ranges
       
       
      Algorithm library
      Constrained algorithms and algorithms on ranges(C++20)
      Constrained algorithms, e.g.ranges::copy,ranges::sort, ...
      Execution policies(C++17)
      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
      (C++11)
      (C++17)
      Lexicographical comparison operations
      Permutation operations
      C library
      Numeric operations
      Operations on uninitialized memory
       
      Constrained algorithms
      All names in this menu belong to namespacestd::ranges
      Non-modifying sequence operations
      Modifying sequence operations
      Partitioning operations
      Sorting operations
      Binary search operations (on sorted ranges)
             
             
      Set operations (on sorted ranges)
      Heap operations
      Minimum/maximum operations
      Permutation operations
      Fold operations
      Operations on uninitialized storage
      Return types
       
      Defined in header<algorithm>
      Call signature
      template<std::input_iterator I1,std::sentinel_for<I1> S1,

               std::input_iterator I2,std::sentinel_for<I2> S2>
      requiresstd::indirectly_swappable<I1, I2>
      constexpr swap_ranges_result<I1, I2>

          swap_ranges( I1 first1, S1 last1, I2 first2, S2 last2);
      (1)(since C++20)
      template<ranges::input_range R1,ranges::input_range R2>

      requiresstd::indirectly_swappable<ranges::iterator_t<R1>,ranges::iterator_t<R2>>
      constexpr swap_ranges_result<ranges::borrowed_iterator_t<R1>,
                                   ranges::borrowed_iterator_t<R2>>

          swap_ranges( R1&& r1, R2&& r2);
      (2)(since C++20)
      Helper types
      template<class I1,class I2>
      using swap_ranges_result=ranges::in_in_result<I1, I2>;
      (3)(since C++20)
      1) Exchanges elements between first range[first1first1+ M) and second range[first2first2+ M) viaranges::iter_swap(first1+ i, first2+ i), whereM=ranges::min(ranges::distance(first1, last1),ranges::distance(first2, last2)).
      The ranges[first1last1) and[first2last2) must not overlap.
      2) Same as(1), but usesr1 as the first range andr2 as the second range, as if usingranges::begin(r1) asfirst1,ranges::end(r1) aslast1,ranges::begin(r2) asfirst2, andranges::end(r2) aslast2.

      The function-like entities described on this page arealgorithm function objects (informally known asniebloids), that is:

      Contents

      [edit]Parameters

      first1, last1 - the iterator-sentinel pair defining the firstrange of elements to swap
      first2, last2 - the iterator-sentinel pair defining the secondrange of elements to swap
      r1 - the first range of elements to swap
      r2 - the second range of elements to swap.

      [edit]Return value

      {first1+ M, first2+ M}.

      [edit]Complexity

      ExactlyM swaps.

      [edit]Notes

      Implementations (e.g.MSVC STL) may enable vectorization when the iterator type modelscontiguous_iterator and swapping its value type calls neither non-trivial special member function norADL-foundswap.

      [edit]Possible implementation

      struct swap_ranges_fn{template<std::input_iterator I1,std::sentinel_for<I1> S1,std::input_iterator I2,std::sentinel_for<I2> S2>    requiresstd::indirectly_swappable<I1, I2>constexpr ranges::swap_ranges_result<I1, I2>        operator()(I1 first1, S1 last1, I2 first2, S2 last2)const{for(;!(first1== last1 or first2== last2);++first1,++first2)ranges::iter_swap(first1, first2);return{std::move(first1), std::move(first2)};} template<ranges::input_range R1,ranges::input_range R2>    requiresstd::indirectly_swappable<ranges::iterator_t<R1>,ranges::iterator_t<R2>>constexpr ranges::swap_ranges_result<ranges::borrowed_iterator_t<R1>,ranges::borrowed_iterator_t<R2>>        operator()(R1&& r1, R2&& r2)const{return(*this)(ranges::begin(r1),ranges::end(r1),ranges::begin(r2),ranges::end(r2));}}; inlineconstexpr swap_ranges_fn swap_ranges{};

      [edit]Example

      Run this code
      #include <algorithm>#include <iostream>#include <list>#include <string_view>#include <vector> auto print(std::string_view name,autoconst& seq,std::string_view term="\n"){std::cout<< name<<" : ";for(constauto& elem: seq)std::cout<< elem<<' ';std::cout<< term;} int main(){std::vector<char> p{'A','B','C','D','E'};std::list<char> q{'1','2','3','4','5','6'};     print("p", p);    print("q", q,"\n\n"); // swap p[0, 2) and q[1, 3):    std::ranges::swap_ranges(p.begin(),                             p.begin()+4,                             std::ranges::next(q.begin(),1),                             std::ranges::next(q.begin(),3));    print("p", p);    print("q", q,"\n\n"); // swap p[0, 5) and q[0, 5):    std::ranges::swap_ranges(p, q);     print("p", p);    print("q", q);}

      Output:

      p : A B C D Eq : 1 2 3 4 5 6 p : 2 3 C D Eq : 1 A B 4 5 6 p : 1 A B 4 5q : 2 3 C D E 6

      [edit]See also

      (C++20)
      swaps the values referenced by two dereferenceable objects
      (customization point object)[edit]
      swaps the values of two objects
      (customization point object)[edit]
      swaps two ranges of elements
      (function template)[edit]
      swaps the elements pointed to by two iterators
      (function template)[edit]
      swaps the values of two objects
      (function template)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/algorithm/ranges/swap_ranges&oldid=180480"

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