-- Chapter 4 - Programming exercixe 2
                                       -- Chapter 4 - Program 2
with Text_IO;
use Text_IO;

procedure Ch04_2 is

   package Int_IO is new Text_IO.Integer_IO(INTEGER);
   use Int_IO;

   package Enum_IO is new Text_IO.Enumeration_IO(BOOLEAN);
   use Enum_IO;

   Index, Count           : INTEGER := 12;
   Truth, Lies, Question  : BOOLEAN;

begin
   Truth := Index = Count;      -- This is TRUE
   Put("Truth now has the value of ");
   Put(Truth);
   New_Line;
   Lies := Index < Index;       -- This is FALSE
   Put("Lies now has the value of ");
   Put(Lies);
   New_Line;

                            -- Examples of all BOOLEAN operators
   Question := Index =  Count;      -- Equality
   Question := Index /= Count;      -- Inequality
   Question := Index <  Count;      -- Less than
   Question := Index <= Count;      -- Less than or equal
   Question := Index >  Count;      -- Greater than
   Question := Index >= Count;      -- Greater than or equal
   Put("Question now has the value of ");
   Put(Question);
   New_Line;

                       -- Examples of composite BOOLEAN expressions
   Question := Index = 12 and Count = 12 and Truth and TRUE;
   Question := Index /= 12 or FALSE or Count > 3 or Truth;
   Question := (Truth or Lies) and (Truth and not Lies);
   Question := Truth xor Lies;
   Put("Question now has the value of ");
   Put(Question);
   New_Line;

                       -- now for short circuit evaluation
   Question := Index /= Count and then Index = 9/(Index - Count);
   Question := Index = Count or else  Index = 9/(Index - Count);
   Question := (Index = Count) or else (Index = 9/(Index - Count));
   Put("Question now has the value of ");
   Put(Question);
   New_Line;

end Ch04_2;




-- Result of execution

-- Truth now has the value of TRUE
-- Lies now has the value of FALSE
-- Question now has the value of TRUE
-- Question now has the value of TRUE
-- Question now has teh value of TRUE