WITH ada.text_io;
WITH ada.integer_text_io;
PACKAGE stack IS
TYPE aStack IS ARRAY (1..20) OF integer;
PROCEDURE push (someStack :IN OUT aStack;
                someValue : IN integer); 
PROCEDURE pop (someStack :  IN OUT aStack; 
					someValue : OUT integer);
FUNCTION isFull (someStack : IN aStack) RETURN boolean;
FUNCTION isEmpty (someStack : IN aStack) RETURN boolean;
PROCEDURE peek (someStack : IN aStack; 
                someValue : OUT integer);
END stack;