function positions = randomwalkthresh(p, thresh)
% computes a single random walk
%
% Arguments:
% p: the probability for an upward step
% thresh: compute the random walk until abs(pos) is larger than thresh
%
% Returns:
% positions: vector with positions of the random walker

positions = [0.0];
i = 2;
while true
	r = rand(1);
	if r < p
		positions(i) = positions(i-1) + 1;
	else
		positions(i) = positions(i-1) - 1;
	end
	if abs(positions(i)) > thresh
		break
	end
	i = i + 1;
end
end