1.3. What is Computer Science?

With a little understanding of computers and programming, we can now turn our attention to computer science, often abbreviated to CS. Your first thought might be, “Surely that is the study of computers! We can study how they work, how they are made, …”

While that describes part of the field of computer science, it is a relatively small part. More broadly, CS is the study of what we can do with computers. Computer scientists use computers and programming to solve problems, and they are constantly using them to solve new problems or finding better solutions than those previously discovered.

These solutions are often in the form of programs or algorithms, high-level descriptions of the steps a computer should follow, as opposed to the specific instructions given to the CPU. For example, people have put a lot of work into finding algorithms for rearranging values to be in a certain order, such as putting numbers into increasing order, words into alphabetical order, and so on. These are known as sorting algorithms, and people have developed a wide range of them.

The input and output of a sorting algorithm. Simple enough. Now imagine needing to sort millions of words…

Why expend so much effort for solutions to such a simple problem? Because sorting is broadly applicable in a wide range of situations, and we have a lot of data we want to sort. As users of software, we very often want output or results shown to us in sorted order, because it’s easier for us to use that way. And software itself, other algorithms, benefit from having data sorted as well. Sorting turns out to be a very common step in the solutions of many other problems. Every time you search for something on the web, for example, the search engine isn’t scanning through everything on the internet each time; instead, it’s using a variety of pre-sorted lists to look things up quickly and efficiently.

So sorting and the development of efficient algorithms for sorting is just one tiny, tiny piece of computer science. Wikipedia provides an overview of the subfields of computer science. It’s a wide range, but it all fits within the questions: What can we do with computers? And how can we do those things efficiently?

And that is just the science or research part of computer science. The application of computer science is much broader still. Again, the focus is on doing things and solving problems with computers, and this has found its way into just about every field imaginable. Businesses are run with software to manage data and automate processes; other sciences use computers to run experiments and analyze data; artists are creating algorithmic art and interactive art pieces; computers pervade the creation and consumption of entertainment media; … the examples are effectively endless. In all of these cases, the key skill being applied is not building the computer itself, but rather programming it and coming up with the instructions it will follow to accomplish one’s goal.

And so this is why this book focuses on teaching programming. Knowing how to program and how to solve problems with computers is a critical foundation for computer science and data science.

Check your understanding

Q-1: Which of the following best completes the sentence. (Many are true to very limited extents, but there is one that fits best by far.)

“Computer science is the study of …”

• ... who invented computers.
• That is a relevant side interest, but it is not the focus of computer science.
• ... what is inside a computer.
• That is a small piece of studying computer science, but it is not the focus of the field.
• ... telescopes.
• Nope!
• ... how to build computers.
• This is well worth learning, but in computer science we *start* with a working computer and then think about how we can use it.
• ... what computers can do.
• This is the main question of interest, and it is asked and answered in many ways.