A* Pathfinding Tutorial 01 (Pseudocode)

OPEN //the set of nodes to be evaluated
CLOSED //the set of nodes already evaluated
add the start node to OPEN

loop
	current = node in OPEN with the lowest f_cost
	remove current from OPEN
	add current to CLOSED

	if current is the target node //path has been found
		return

	foreach neighbour of the current node
		if neighbour is not traversable or neighbour is in CLOSED
			skip to the next neighbour

		if new path to neighbour is shorter OR neighbour is not in OPEN
			set f_cost of neighbour
			set parent of neighbour to current
			if neighbour is not in OPEN
				add neighbour to OPEN