Instructions

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

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

1. Check how many birds visited today

Implement the today() function to return how many birds visited your garden today. 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.

2. Increment today's count

Implement the increment_todays_count() function to increment today's count:

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

Implement the has_day_without_birds() function that returns TRUE if there was a day at which zero birds visited the garden; otherwise, return FALSE:

4. Calculate the number of visiting birds for the first number of days

Implement the count_for_first_days() function that returns the number of birds that have visited your garden from the start of the week, but limit the count to the specified number of days from the start of the week.

5. 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 busy_days() function to return the number of busy days:

6. Calculate the running total of bird visits over the last week

You are curious how many birds in total have visited so far this week. Calculate cumulative totals for each day.

7. Sort day names by how busy they are

You suspect that bird visits are affected by patterns of nearby road traffic, so different on weekends versus weekdays.

Sort the day abbreviations in descending order of how many birds visited.