spiral.cpp

#include <iostream>
#include <map>

int main() {
	int x = 0, y = 0;
	enum Direction {Up, Right, Down, Left};
	Direction direction = Up;
	int max_extent = 1;
	int extent = 0;
	std::map<Direction, const char *> dirs {{Up, "up"}, {Right, "right"}, {Down, "down"}, {Left, "left"}};
	for (int i = 0; i < 64; ++i) {
		switch (direction) {
			case Up:    --y; break;
			case Right: ++x; break;
			case Down:  ++y; break;
			case Left:  --x; break;
		}

		std::cout << x << ", " << y << " " << dirs[direction] << "\n";

		if (++extent == max_extent) {
			extent = 0;
			switch (direction) {
				case Up:    direction = Right; break;
				case Right: direction = Down; ++max_extent; break;
				case Down:  direction = Left;  break;
				case Left:  direction = Up;   ++max_extent; break;
			}
		}
	}
}