Welcome to the data structures course! In this course, we are going to learn about operations on collections of data.

But first, what is data? Data is information: it tells us something. Data is also text, since it is something that can be written down in a notebook. Here are some examples of data:

• The population of New York City.
• A list of 10 tallest mountains in the world.
• Dimensions of a car.
• A person's name.
• Michael Jordan's career statistics.

More concretely, data is a collection of one or more values.

Everyday, we work with data to perform essential tasks. For instance, our phones keep a list of phone numbers for all of our friends. When we want to call or message someone, the phone must first find that person on the contacts list. We can also add new contacts, edit existing contacts if their phone number changed, and delete existing contacts.

We are not going to build a phone application in this course, but we will explore logical ways to organize and operate on collections of values such as phone numbers. These ideas are not only essential to build phone applications, but they teach us how to write any computer program that works with data.

Alternatively, we can think of this course as a math course where we operate on collections of numbers (rather than just one or a few numbers).