Object-oriented Software in Ada 95

Appendix D 417
with Ada.Text_Io, Ada.Integer_Text_Io, Class_Queue_Int;
use Ada.Text_Io, Ada.Integer_Text_Io, Class_Queue_Int;
procedure Main is
Number_Queue : Queue; --Queue of numbers
Action : Character; --Action
Number : Integer; --Number processed
begin
while not End_Of_File loop
while not End_Of_Line loop
begin
Get( Action );
case Action is --Process action
when '+' =>
Get( Number ); Add(Number_Queue,Number);
Put("add number = "); Put(Number); New_Line;
when '-' =>
Sub(Number_Queue,Number);
Put("remove number = "); Put(Number); New_Line;
when others =>
Put("Invalid action"); New_Line;
end case;
exception
when Queue_Error =>
Put("Exception Queue_error"); New_Line;
when Data_Error =>
Put("Not a number"); New_Line;
when End_Error =>
Put("Unexpected end of file"); New_Line; exit;
end;
end loop;
Skip_Line;
end loop;
end Main;
From chapter 19
A task type which allows repeated calculations of a factorial value to be made is:
package Pack_Factorial is
task type Task_Factorial is
entry Calculate( F:in Natural );
entry Deliver( Res:out Natural );
entry Finish;
end Task_Factorial;
end Pack_Factorial;
--Specification
--Rendezvous
--Rendezvous
--Rendezvous
© M A Smith - May not be reproduced without permission