Data Modeling 2

Practice: Last 8

Created By: Geoffrey Challen

/ Version: 2020.9.0

Create a public class called Last8. You should expose two public methods:

• add: adds a value, does not return a value
• last: returns an array containing the last 8 values that were added, in any order.

You do not need a constructor, but you can add an empty one if you need. Until 8 values have been added you should return 0s in their place.

For example, here's how an instance of Last8 should work:

Do not create a huge array to save the values. Submissions that do will be marked incorrect.

Practice: Closest Point

Created By: Geoffrey Challen

/ Version: 2022.9.0

Create a public class named ClosestPoint, which we'll use to track the closest location to an initial location. ClosestPoint should provide a public constructor accepting a single Location as its only parameter, which sets the origin. assert that the initial Location is not null. The Location class stores latitude and longitude values as doubles, which you can retrieve using getLatitude and getLongitude.

ClosestPoint provides two public methods. add accepts a new Location and, if it is closer to the origin passed to the constructor than any other location previously passed to add, it updates the closest location accordingly. add should also assert that the passed Location is not null. getClosest returns the closest Location passed to add, or null if add has not yet been called.

A few notes on how to approach this problem. You should calculate distance between two locations in the usual way for points on a flat surface. (We're assuming, for the sake of this problem, that the Earth is, in fact, flat.) However, because floating point math is sensitive to ordering, you should take care in how you compare two distances. With doubles, it is usually safer to not say first > second and instead first - second > delta, where delta is a small value. For this problem, use a delta of 0.0001.

Homework: Last 4 In Order

Created By: Geoffrey Challen

/ Version: 2020.9.1

Create a public class called Last4Ordered. You should expose two public methods:

• add: adds a value, does not return a value
• last: returns an array containing the last 4 values that were added in the order they were added.

You do not need a constructor, but you can add an empty one if you need. Until 4 values have been added you should return 0s in their place.

For example, here's how an instance of Last4Ordered should work:

Do not create a huge array to save the values. Submissions that do will be marked incorrect.

This problem is harder than it looks! A suggestion is to handle the cases until the array is initially filled separately. Once four values have been added, you will need to shift values around before adding a new one.

Do not use a List to solve this problem.