def every_sunday(d1, d2)
one_day = d1.is_a?(Time) ? 60*60*24 : 1
sunday = d1 + ((7-d1.wday) % 7) * one_day
while sunday < d2
yield sunday
sunday += one_day * 7
end
end
def print_every_sunday(d1, d2)
every_sunday(d1, d2) { |sunday| puts sunday.strftime("%x")}
end
print_every_sunday(Time.local(2006, 1, 1), Time.local(2006, 2, 4))