Averages/Mean time of day: Difference between revisions

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=={{header|Ada}}==

<lang Ada>with Ada.Calendar.Formatting;

with Ada.Command_Line;

with Ada.Numerics.Elementary_Functions;

with Ada.Strings.Fixed;

with Ada.Text_IO;

procedure Mean_Time_Of_Day is

subtype Time is Ada.Calendar.Time;

subtype Time_Of_Day is Ada.Calendar.Day_Duration;

subtype Time_String is String (1 .. 8); -- "HH:MM:SS"

type Time_List is array (Positive range <>) of Time_String;

function Average_Time (List : Time_List) return Time_String is

function To_Time (Time_Image : Time_String) return Time

is (Ada.Calendar.Formatting.Value ("2000-01-01 " & Time_Image));

function To_Time_Of_Day (TS : Time) return Time_Of_Day is

use Ada.Calendar.Formatting;

Hour_Part : constant Time_Of_Day := 60.0 * 60.0 * Hour (TS);

Min_Part : constant Time_Of_Day := 60.0 * Minute (TS);

Sec_Part : constant Time_Of_Day := Time_Of_Day (Second (TS));

begin

return Hour_Part + Min_Part + Sec_Part;

end To_Time_Of_Day;

function To_Time_Image (Angle : Time_Of_Day) return Time_String

is

use Ada.Calendar.Formatting;

TOD : constant Time := Time_Of

(Year => 2000, Month => 1, Day => 1, -- Not used

Seconds => Angle);

begin

return Ada.Strings.Fixed.Tail (Image (TOD), Time_String'Length);

end To_Time_Image;

function Average_Time_Of_Day (List : Time_List) return Time_Of_Day is

use Ada.Numerics.Elementary_Functions;

Cycle : constant Float := Float (Time_Of_Day'Last);

X_Sum, Y_Sum : Float := 0.0;

Angle : Float;

begin

for Time_Stamp of List loop

Angle := Float (To_Time_Of_Day (To_Time (Time_Stamp)));

X_Sum := X_Sum + Cos (Angle, Cycle => Cycle);

Y_Sum := Y_Sum + Sin (Angle, Cycle => Cycle);

end loop;

Angle := Arctan (Y_Sum, X_Sum, Cycle => Cycle);

if Angle < 0.0 then

Angle := Angle + Cycle;

elsif Angle > Cycle then

Angle := Angle - Cycle;

end if;

return Time_Of_Day (Angle);

end Average_Time_Of_Day;

begin

return To_Time_Image (Average_Time_Of_Day (List));

end Average_Time;

use Ada.Command_Line;

List : Time_List (1 .. Argument_Count);

begin

if Argument_Count = 0 then

raise Constraint_Error;

end if;

for A in 1 .. Argument_Count loop

List (A) := Argument (A);

end loop;

Ada.Text_IO.Put_Line (Average_Time (List));

exception

when others =>

Ada.Text_IO.Put_Line ("Usage: mean_time_of_day <time-1> ...");

Ada.Text_IO.Put_Line (" <time-1> ... 'HH:MM:SS' format");

end Mean_Time_Of_Day;</lang>

{{out}}

<pre>

% ./mean_time_of_day 23:00:17 23:40:20 00:12:45 00:17:19

23:47:43