MODULE sign1;
(*---------------------------------------------------------
File name: sign.pm
Author: AG, MM
Date: 5/27/05 

Problem: This program calls a procedure that checks the sign of 
all elements of chain.

	sign1(x) = 	 1, if x > 0
			-1, if x < 0
			0, if x = 0
			
Example of Execution:
	 L1:  4 -1  3 -2  3 -1 -2  4  3  0 -1  0 -2  4 -1
	L2:  1 -1  1 -1  1 -1 -1  1  1  0 -1  0 -1  1 -1

Cycles:
2 assignments
*)
(*----------------------------------------------------------
		CONFIGURATION
----------------------------------------------------------*)
CONST  MAXCELLS=1024; (* MAXCELLS cells in one line *)

CONFIGURATION chain[0..(MAXCELLS - 1)];
CONNECTION
		left: chain [i] -> chain[(i-1) MOD MAXCELLS];
		right: chain[i] -> chain[(i+1) MOD MAXCELLS];
(*----------------------------------------------------------
		VARIABLES
----------------------------------------------------------*)
VAR 
		L1, LRes: chain OF INTEGER;  	(* Line always "L#" *)

(*----------------------------------------------------------
		PROCEDURES
----------------------------------------------------------*)
PROCEDURE Sign();
(*----------------------------------------------------------
		PROCEDURE MAIN
----------------------------------------------------------*)
BEGIN
	LRes := 0;
	IF L1 > 0 THEN
		LRes := 1;
	END; (*IF *)
	IF L1 < 0 THEN
		LRes := -1;
	END; (* IF *)
END Sign;   (* Result is in Global variable F *)
(*-----------------------------------------------------------
		MAIN
------------------------------------------------------------*)
BEGIN
	(* initialize data *)
	L1 := RandomInt(chain) MOD 5;
		
	IF L1 < 3 THEN
		L1 := L1 * (-1);
	END; (* IF *)
	Sign();
	
	(* display data *)
	IF ID(chain) < 16 THEN
		WriteString(" L1: "); WriteInt(L1, 2); WriteLn;
		WriteString(" LRes: "); WriteInt(LRes, 2); WriteLn;
	END; (* IF *)
END sign1.