We use programming to instruct a computer. Computers include smartphones (such as the iPhone), tablets, game consoles (such as the PlayStation), and a lot more. We say that a computer runs a program, which means that when you open your favorite game or application (also referred to as an app) on your PlayStation or on your iPhone, the device will know how to interpret and execute the program, which in this case is your game or application. A program is simply a set of instructions that your device is able to understand. We can also consider these instructions as a recipe for the device. The recipe will tell your iPhone what your favorite game is all about-everything from the colors of your avatar, to the text in the menus, to what happens when you tap on an enemy or on an animal in a game. This recipe can be written in many ways depending on your personal preference and the device that is supposed to run it. The programming language refers to the language you choose to write your program in.
This chapter will go through the following topics:
Introducing the Swift programming language
Why is programming important?
What the reader can expect from this book
Let's imagine this simple application for an iPhone-Movie Night, which has a list of your favorite movies. If the list is longer than the height of your device, you are able to scroll through the list by swiping up and down. You can add movies to your list by tapping a button and entering a name for the movie and you can delete them again by swiping left on the movie in the list. The idea of the app is to keep a list of your favorite movies so that you can remember them when having a movie night. In this case, the program is the application (called Movie Night), the device is the iPhone, and the instructions of the application could be the colors of the background and texts, the list in which you can scroll, and the add and delete functionalities. Programming is about creating these set of instructions so that we are able run our application on our iPhone. If you're excited about creating your own Movie Night app that you can use with your friends, then read along as this is an application we will build together in Chapter 14, Movie Night - iOS App.
There are many reasons for why programming is becoming increasingly popular. The result of doing programming allows people to connect through social media, such as Facebook and Instagram; it allows people to be entertained through immersive and rich games; and it allows people to learn and become educated in a fun and engaging manner using interactive applications. Programming has enabled us to share knowledge across geographical boundaries in a way that seemed impossible before programming existed. Programming has helped us automate tasks such as selling tickets at the local train station, paying in a faster and secure way using our smartphone, and programming has helped us measure the well-being of humans in order to give the right treatment at the right moment.
Programming has made it possible for us to instruct a computer on how to perform certain tasks in a more efficient and reliable manner than would ever be possible for a human being. There are natural limits to how much a person can do within the 24 hours of a day or within the lifetime of a person's life. Also, it is costly to have a person perform tedious tasks that seem repetitive, time-consuming, or based on deterministic behavior, such as calculations. As it is costly and it can be hard to find the right or, simply, enough people, it also means that it does not scale very well. Computers are relatively cheap and can be considered as fairly stable. If computers break, they are easy to replace, which means that performing tasks using computers scales really well. Just imagine a bank system without computers; imagine people sitting and keeping track of each person's balance and trying to keep it synchronized across large geographical distances.
Imagine the recent Pokémon smartphone game being done without computers. With no computers, there would need to be maps distributed to each player that show exactly where a Pokémon is located and people (from the game) would need to be at the actual geographical location in order to tell or validate that the Pokémon trainer had just found a Pokémon. Also, in order to keep track of Pokémon caught, and not to mention the outcome of a battle with another trainer, a lot needs to be handled on paper by the player. Without computers, one can easily think of problems with consistent play experiences, such as verifying that a player does not cheat and modifying the game rules as the game evolves, just to name a few. In general, computers have the ability to enhance our daily life, and we quickly forget what the world would look like without computers. Traditionally, programming has had a steep learning curve and, in general, been inaccessible by younger people. Today, programming is widely used and we have many different languages and tools that solve a lot of different types of problems. This means that it has been possible to lower the learning curve and involve people of different ages and with different capabilities.
This book gives you an introduction to the programming language, Swift. Swift is a fairly new programming language (version 1 came out in September 2014) and the language can be used to write programs for most of the Apple devices, including the iPhone, iPad, Apple Watch, MacBook, and Apple TV. Throughout the book, we will gradually introduce you to more and more programming concepts until we have enough knowledge to start creating our own programs. The book will let you create programs such as a small Pokémon game, where Pokémon will be able to battle each other.
We will also be creating an app to deliver pizzas in outer space and the aforementioned Movie Night app to keep a list of your favorite movies. After creating our programs, you will be able to install the applications on an iPhone and show it to your friends. After being introduced to Swift and the knowledge and tools required to create an application for the iPhone, you should be able to continue to explore this area of programming. You should not only be able to continue working on the applications we create throughout this book, but also be capable of continuing the learning journey using other books or Internet resources. By using the skills provided in this book along with some imagination, a lot of fun and useful applications can be created for iOS devices such as the iPhone.
In this chapter, we looked at what programming actually is, why it is useful, and examples of what we use programming for. We discussed what a world without programming would look like and we looked at a short introduction to the Swift programming language. Lastly, we introduced what the reader can expect to learn when reading this book and how this can be used moving further into the world of programming.
In the next chapter, we will go over the practical part of getting the user set up with the right tools in order to begin programming.