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std::experi...cal_compare(3)  C++ Standard Libary std::experi...cal_compare(3)

NAME
       std::experimental::ranges::lexicographical_compare   -  std::experimen-
       tal::ranges::lexicographical_compare

Synopsis
	  Defined in header <experimental/ranges/algorithm>
	  template< InputIterator I1, Sentinel<I1> S1, InputIterator I2,
	  Sentinel<I2> S2,

		    class Proj1	= ranges::identity, class Proj2	=
	  ranges::identity,
		    class Comp = ranges::less<>	>
	      requires	IndirectStrictWeakOrder<Comp,  projected<I1,   Proj1>,
       (1) (ranges TS)
	  projected<I2,	Proj2>>
	  bool lexicographical_compare(	I1 first1, S1 last1, I2	first2,	S2
	  last2,
					Comp comp = Comp{},

					Proj1 proj1 = Proj1{}, Proj2 proj2 =
	  Proj2{} );
	  template< InputRange R1, InputRange R2,

		    class Proj1	= ranges::identity, class Proj2	=
	  ranges::identity,
		    class Comp = ranges::less<>	>
	      requires IndirectStrictWeakOrder<Comp,
	  projected<ranges::iterator_t<R1>,			       Proj1>,
       (2) (ranges TS)

	   projected<ranges::iterator_t<R2>, Proj2>>
	  bool lexicographical_compare(	R1&& r1, R2&& r2, Comp comp = Comp{},

					Proj1 proj1 = Proj1{}, Proj2 proj2 =
	  Proj2{} );

	  1) Checks if the first range [first1,	 last1)	 is  lexicographically
       less than the
	  second  range	[first2, last2). Elements are compared using the given
       binary
	  comparison function comp, after being	projected with proj1 and proj2
       respectively.
	  2) Same as (1), but uses r1 as the first source range	and r2 as  the
       second source
	  range,  as  if using ranges::begin(r1) as first1, ranges::end(r1) as
       last1,
	  ranges::begin(r2) as first2, and ranges::end(r2) as last2.

	  Lexicographical comparison is	an operation with the following	 prop-
       erties:

	    * Two ranges are compared element by element.
	    *  The  first  mismatching	element	defines	which range is lexico-
       graphically less	or
	      greater than the other.
	    * If one range is a	prefix of another, the shorter range is	 lexi-
       cographically less
	      than the other.
	    *  If  two	ranges	have  equivalent  elements and are of the same
       length, then the
	      ranges are lexicographically equal.
	    * An empty range is	 lexicographically  less  than	any  non-empty
       range.
	    * Two empty	ranges are lexicographically equal.

Parameters
	  first1, last1	- the first range of elements to examine
	  r1		- the first range of elements to examine
	  first2, last2	- the second range of elements to examine
	  r2		- the second range of elements to examine
	  comp		 -  comparison function	to apply to the	projected ele-
       ments
	  proj1		- projection to	apply to the  elements	in  the	 first
       range
	  proj2		 -  projection	to apply to the	elements in the	second
       range

Return value
	  true if the first range is lexicographically less than the second.

Complexity
	  At most 2min(N1, N2) applications of the comparison operation, where
       N1 = last1 -
	  first1 and N2	= last2	- first2.

Possible implementation
	  template<InputIterator I1, Sentinel<I1> S1, InputIterator  I2,  Sen-
       tinel<I2> S2,
		   class Proj1 = ranges::identity, class Proj2 = ranges::iden-
       tity,
		   class Comp =	ranges::less<>>
	      requires	 IndirectStrictWeakOrder<Comp,	projected<I1,  Proj1>,
       projected<I2, Proj2>>
	  bool lexicographical_compare(I1 first1,  S1  last1,  I2  first2,  S2
       last2,
				       Comp comp = Comp{},
				       Proj1  proj1  =	Proj1{}, Proj2 proj2 =
       Proj2{})
	  {
	      for (; (first1 !=	last1) && (first2 != last2); (void)  ++first1,
       (void) ++first2)
	      {
		  if (ranges::invoke(comp, ranges::invoke(proj1, *first1),
					   ranges::invoke(proj2, *first2)))
		      return true;
		  if (ranges::invoke(comp, ranges::invoke(proj2, *first2),
					   ranges::invoke(proj1, *first1)))
		      return false;
	      }
	      return (first1 ==	last1) && (first2 != last2);
	  }

Example
	   This	section	is incomplete
	   Reason: no example

See also
				  returns  true	 if one	range is lexicographi-
       cally less than
	  lexicographical_compare another
				  (function template)
	  equal			  determines if	two sets of elements  are  the
       same
				  (function template)

Category:
	    * Todo no example

http://cppreference.com		  2024.06.10	  std::experi...cal_compare(3)

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