Object-oriented Software in Ada 95

410 Appendix D
with Ada.Text_Io, Ada.Float_Text_Io, Class_Performance, Class_Tui;
use Ada.Text_Io, Ada.Float_Text_Io, Class_Performance, Class_Tui;
procedure Main is
procedure Process(Per:in out Performance; Name:in String) is
function Money_Image( M:in Money ) return String is
Res : String( 1 .. 10 ); --String of 10 characters
begin
Put( Res, M, Aft=>2, Exp=>0 ); --2 digits - NO exp
return Res;
end Money_Image;
Screen : Tui; --The TUI screen
Tickets : Integer; --Tickets being processed
begin
loop
Message( Screen, "Performance is " & Name );
Menu( Screen, "Book", "Cancel", "Seats free", "Sales" );
case Event( Screen ) is
when M_1 =>
--Book
Dialog(Screen, "Number of seats to book", Tickets);
if Tickets>0 and then Tickets
--Cancel
Dialog(Screen, "Number of seats to return", Tickets);
if Tickets > 0 then
Cancel( Per, Tickets );
else
Message( Screen, "Not a valid number of tickets" );
end if;
when M_3 =>
--Free
Message( Screen, "Number of seats free is" &
Integer'Image( Seats_Free(Per) ) );
when M_4 =>
--Value
Message( Screen, "Value of seats sold is £" &
Money_Image( Sales(Per) ) );
when M_Quit =>
--Exit
exit;
end case;
end loop;
end Process;
Afternoon, Early_Evening, Evening : Performance;
Main_Menu : Tui;
begin
loop
Menu(Main_Menu, "Afternoon", "Early Evening", "Evening", "");
case Event( Main_Menu ) is
when M_1 => Process( Afternoon, "Afternoon" );
when M_2 => Process( Early_Evening, "Early evening" );
when M_3 => Process( Evening, "Evening" );
when M_Quit => exit;
when others => Message( Main_Menu, "Try again");
end case;
end loop;
end Main;
From chapter 6
A fragment of code showing a data structure that represents a computer system.
© M A Smith - May not be reproduced without permission