Developing applications for iOS: where to start?

Every day, the number of people who dream of learning how to create programs increases. After gathering information on the network, they come to the idea that the most promising is the development of applications for iOS - the operating system from Apple. In fact, dreaming is one thing, and programming is another. Creating your own application is not easy. But it's also not difficult to get over it. What is needed for this?

Programming language

To write programs for a specific platform, you need to use a specific programming language. The development of applications for iOS and Android is different. If the platform from the "Google" to choose the language of Java, then for iOS the choice is between Objective-C and Swift. For a long time, development for the iOS platform was carried out only with the help of the Objective-C programming language. Despite the fact that he is many years old, he is still developing and used by a large number of developers. But its minus is a high threshold of occurrence.

Since Apple's most important source of revenue is its application store, employees are interested in more useful and interesting utilities. For this reason, a regular conference is held for developers, on which they talk about changes in operating systems. In 2014, developers showed the latest programming language Swift, which is developing applications for iOS. Swift is easy to learn, since it has very simple syntax and is strongly typed. For those who want to master the creation of applications for iOS, this language suits very well.

What you need to start

In addition to the basic knowledge of programming, you need to have the following:

• Computer or laptop with OSX operating system on board;
• Xcode development environment, which is free.

This set allows you to run applications in a special simulator directly on your computer. But you need to keep in mind that in the future, you may need to pay $ 99 to get an annual subscription to the developer program. After payment, you will be able to:

• Run the developed programs are not in the simulator, but on real devices;
• Place applications in the App Store;
• Download new versions of the development environment and iOS.

In new versions of Xcode, an element appeared, such as a "sandbox" called Playground. Here the developer can experiment with a new programming language.

Many people want to start writing programs, but they think that it is extremely difficult. Of course, in order to become a professional, you need to have a lot of knowledge and vast experience behind them. But in order to create a small application, there is no need to be a professional.

How does the development of applications for iOS and Android start? Training takes place in practice. Therefore, we must start with it. A lot of theory is not always good. After all, if a person reads ten textbooks on programming from cover to cover, he will not become a programmer. We must act.

Playground

This "sandbox" is a wonderful environment for learning a programming language. How does she look? The user enters a line of code and immediately sees the result. After it becomes clear that the written fragment works as it should, you can simply transfer it to the project. Using the "sandbox" you can solve such problems as:

• Mastering the syntax of the programming language;
• Improve programming skills by experimenting with new APIs;
• Simple arithmetic calculations;
• The development of a new algorithm and monitoring of each step.

Developing applications for iOS: where to start

The theory is, of course, good, but, as stated earlier, practice is needed. In order to get acquainted with the "sandbox", you need to start the Xcode development environment. After the launch, the user can see the window in which it is proposed to create a new project or run Playground. We need the second item. Now you need to come up with a name and save the "sandbox" to any convenient place on the computer. By the way, the development of applications for iOS on Windows is also possible, but then it will be necessary to solve a large number of problems. This installation of a pirated operating system, and editing of important files, and many errors and departures.

After saving, the same Playground will be launched.

At first glance, there is nothing interesting. But it's worth it to write your code there, as the appearance will change immediately.

First, you can try to write the following:

Var z = 3

For var y = 0; Y <10; ++ y {

Z + = z * y

}

Z

Println ("result: (z)")

After that, the "sandbox" will change its appearance. The column on the right (results pane) shows the values for each row that are obtained after execution. Also, in the right column, you can turn on the display of the temporary panel, which allows you to track changes in the time of the selected expression. Here, the console output with the text displayed by the program is displayed.

Commenting on the code

Development of applications for iOS, as well as for other platforms, does not do without comments, which are necessary to make it easier for the developer to navigate in the code. Comments are strings ignored during program execution. They can be either single-line or multi-line.

Variables

So, applications are written in the programming language. The base of any language is made up of variables. Developing applications for iOS and Android without the use of variables is impossible. As you can see from the name, this is a container that contains a variable value. Each variable must have a unique name and can contain both numeric and text values. In the Swift programming language, variables are defined using the words var and let. In the second case, the variable can not be changed and must be initialized at the declaration. In the first case, the variable is initialized immediately before use.

Each variable has some type. These can be strings, floating point numbers (fractional), Boolean values (true and false).

Output of results

The output of the program is displayed in the console. What it is? This is what ensures the user's interaction with the computer. So, the output console used to be called the monitor, and the input console is the keyboard. Now the meaning of the terms has changed slightly. This is the name of the program window for entering and exiting commands. The development of applications for iOS often requires the output of some data. For this purpose, the commands print and println are provided in the Swift language. The first differs from the second in that it automatically starts with a new line.

Functions

The next basic concept in programming is function. This is a sequence of actions that perform a specific task. Each function is able to take some values, as well as return the result. To use this construct, you must first declare it using the func keyword. After it, the name is specified, as well as the parentheses. If any value is to be returned, then after its parentheses, its type is indicated. If the return value is not present, then the type can not be specified or specify an "empty" type - void. The values that the function accepts are in parentheses. To call a function, specify its name and values for the arguments.

You can make sure that the parameter name is specified when the function is called. To do this, it is framed by the symbol "lattice".

So you can write any useful functions that can, for example, calculate the exchange rate, transfer one unit of measure to another. Each time you need to use them, you just need to call these functions, and not write the code again.

Now what?

So, as you can see from the above, the development of applications for iOS own hands may well be on everyone's strength. The main thing is to learn the basics of the programming language, get acquainted with the development environment and practice a lot and often. Practice helps to make significant progress. But what is described here is just the beginning. Further in the world of programming there will be many interesting, complex, fascinating. This will help to always keep the brain in good shape, create something new and make good money. After all, Apple's technology is used all over the world. Therefore, your application will be able to evaluate millions of people.