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# System prepended metadata

title: Lecture 15 Setup/Prep
tags: [Setup]

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tags: Setup
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# Lecture 15 Setup/Prep

We're raised the question of potentially swapping out the data structure to be used for accounts. In particular, since every account has a numeric ID number, we might consider using an array.

We don't need a new starter file for today. We'll add to the code from the end of the previous lecture.

## Prep

Consider the following questions:

- Do you think an array is a good choice of a data structure for accounts, if we want frequently open accounts and look up accounts by number, and sometimes close accounts? Why or why not?
- Assume that we added a unique username to the Customer class. Would an array be useful for helping us quickly access Customers based on their usernames? Why or why not?