如何在Ada中快速排序

Question

如何在Ada中快速排序？ 我也喜欢测试它的功能。 我使用GPS作为IDE

Answer 1

如果Quicksort不是绝对必要的，为什么不使用通用Containers.Generic_Array_Sort程序？

编辑：大多数通用数组排序的实现都将使用Quicksort，因此请检查您的用途，您可能不必实现自己的。

Answer 2

您可以在http://rosettacode.org/wiki/Sorting_algorithms/Quicksort#Ada

获取QuickSort的代码

Answer 3

可以找到Ada中quicksort的示例here。请注意，您需要这三个文件。

Answer 4

代码

使用GNAT GPL 2015在Windows 10上编译。 转自rosettacode quicksort pseudocode。

with Ada.Text_IO;
with Ada.Float_Text_IO;
with Ada.Strings;
with Ada.Strings.Fixed;

procedure Main is

   generic
      type Element is private;
   procedure Generic_Swap (A, B : in out Element);
   procedure Generic_Swap (A, B : in out Element) is
      Temp : constant Element := A;
   begin
      A := B;
      B := Temp;
   end;

   generic
      type Index is (<>);
      type Element is private;
      type Vector is array (Index range <>) of Element;
      with function "<" (Left, Right : Element) return Boolean is <>;
      with function ">" (Left, Right : Element) return Boolean is <>;
   procedure Generic_Quicksort (Item : in out Vector);
   procedure Generic_Quicksort (Item : in out Vector) is
      procedure Swap is new Generic_Swap (Element);
      pragma Suppress (Overflow_Check);
      pragma Suppress (Range_Check);
      Pivot : Element;
      Left : Index;
      Right : Index;
   begin
      if Item'Length > 1 then
         Pivot := Item (Item'Last); -- Choose the pivot element.
         Left := Item'First;
         Right := Item'Last;
         while Left <= Right loop
            while Item (Left) < Pivot loop
               Left := Index'Succ (Left);
            end loop;
            while Item (Right) > Pivot loop
               Right := Index'Pred (Right);
            end loop;
            if Left <= Right then
               Swap (Item (Left), Item (Right));
               Left := Index'Succ (Left);
               Right := Index'Pred (Right);
            end if;
         end loop;
         Generic_Quicksort (Item (Item'First .. Right));
         Generic_Quicksort (Item (Left .. Item'Last));
      end if;
   end;

   type Planet is (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto);
   type Planet_Season_Array is array (Planet range <>) of Float;
   procedure Sort is new Generic_Quicksort (Planet, Float, Planet_Season_Array);
   procedure Put (Item : Planet_Season_Array) is
      use Ada.Text_IO;
      use Ada.Float_Text_IO;
      use Ada.Strings.Fixed;
   begin
      for I in Item'Range loop
         Put (Tail (I'Img, Planet'Width));
         Put (Item (I), 2, 2, 0);
         New_Line;
      end loop;
      New_Line;
   end;

   Item : Planet_Season_Array (Planet) := (0.8, 0.1, 0.4, 0.9, 0.0, 0.7, 0.5, 0.3, 0.7);

begin
   Put (Item);
   Sort (Item);
   Put (Item);
end;

输出

MERCURY 0.80
  VENUS 0.10
  EARTH 0.40
   MARS 0.90
JUPITER 0.00
 SATURN 0.70
 URANUS 0.50
NEPTUNE 0.30
  PLUTO 0.70

MERCURY 0.00
  VENUS 0.10
  EARTH 0.30
   MARS 0.40
JUPITER 0.50
 SATURN 0.70
 URANUS 0.70
NEPTUNE 0.80
  PLUTO 0.90