instructions.md

You're an avid bird watcher that keeps track of how many birds have visited your garden in the last seven days.

You have five tasks, all dealing with the numbers of birds that visited your garden.

1. Check what the counts were last week

For comparison purposes, you always keep a copy of last week's counts nearby, which were: 0, 2, 5, 3, 7, 8 and 4. Implement the BirdCount.last_week method that returns last week's counts:

BirdCount.last_week
# => [0, 2, 5, 3, 7, 8, 4]

2. Check how many birds visited yesterday

Implement the BirdCount#yesterday method to return how many birds visited your garden yesterday. The bird counts are ordered by day, with the first element being the count of the oldest day, and the last element being today's count.

birds_per_day = [2, 5, 0, 7, 4, 1]
bird_count = new BirdCount(birds_per_day)
bird_count.yesterday
# => 4

3. Calculate the total number of visiting birds

Implement the BirdCount#total method to return the total number of birds that have visited your garden:

birds_per_day = [2, 5, 0, 7, 4, 1]
bird_count = new BirdCount(birds_per_day)
bird_count.total
# => 19

4. Calculate the number of busy days

Some days are busier that others. A busy day is one where five or more birds have visited your garden. Implement the BirdCount#busy_days method to return the number of busy days:

birds_per_day = [2, 5, 0, 7, 4, 1]
bird_count = new BirdCount(birds_per_day)
bird_count.busy_days
# => 2

5. Check if there was a day with no visiting birds

Implement the BirdCount#day_without_birds? method that returns true if there was a day at which zero birds visited the garden; otherwise, return false:

birds_per_day = [2, 5, 0, 7, 4, 1]
ird_count = new BirdCount(birds_per_day)
bird_count.day_without_birds?
# => true