TRAFFIC JAM PROCEDURAL (or "Detailed") DESIGN

PROCEDURE Play_Traffic_Jam
	
	Print Welcome
	Call Reset_Board
	Call Display_Board

	WHILE NOT Is_Win 

		Call Take_Turn
		Call Display_Board

	END WHILE


PROCEDURE Take_Turn 
	
	REPEAT
		Show Prompt
		Call Get_Move 
	UNTIL Is_Valid_Move
	Call Update_Board

                        
PROCEDURE Init_Board 

   Set puzzle array to starting configuration
   Set empty position to 6.


PROCEDURE Display_Board
 
   FOR position IN Rocks DO
   
      Convert the marker in Puzzle(pos) to a printable character.
      Print the marker character (>, <, or .)
      
   END LOOP;

   Put blank line
   Put row of dashes
   Put row of rock numbers 1 - 11
   

PROCEDURE Update_Board

   Swap markers in the puzzle at The_Move and Empty_Position
   Empty_Position becomes The_Move

 
FUNCTION Is_Win 

   RETURN  (Puzzle = winning configuration)
   

FUNCTION Is_Valid_Move

   IF The_Move out of bounds THEN RETURN FALSE
   IF Marker at The_Move is Empty THEN RETURN FALSE
   
   CASE Marker at The_Move 

      Facing Right : 
         IF the spot to its right is empty RETURN TRUE
         IF the spot to its right has a Left marker 
            AND the "leapfrog" spot is empty RETURN TRUE

      Facing Left  :
         IF the spot to its left is empty RETURN TRUE
         IF the spot to its left has a Right marker
            AND the "leapfrog" spot is empty RETURN TRUE
        
    END CASE