Home > Articles > Home & Office Computing > Mac OS X

Introducing Xcode 4

  • Print
  • + Share This
This chapter is from the book

Goodbye “Hello, World”

For many people, their first program was something along the lines of the well-known Hello World program shown in Listing 1.1. It is from the classic The C Programming Language by Brian Kernighan and Dennis Ritchie (1978).

Listing 1.1 Hello, World

main( ) {
    printf("hello, world");
}

Many people still think of this as a model of what programming is all about: You start with a blank piece of paper or a blank screen, you type in your code, you run it, you make revisions, and you continue on to the next program on its own blank piece of paper or blank screen.

Today’s programming is based on several commonly used paradigms. Two of the most important have to do with how programs function—declarative and imperative paradigms. A third, object-oriented programming, has to do with the structure of programs.

Working with Imperative and Declarative Programming Paradigms

Today’s apps are much more complex than just printing or displaying a line of text. How do you get from Hello, World to an app such as iTunes? Even an app that appears to be text-based such as Pages in the iWork suite is a far cry from Hello, World. And when you consider that Mac OS X and iOS are basically just very large apps, it is hard to see how they evolved from Hello, World.

When Hello, World first was written, the programming world was already moving away from this linear do this/do that paradigm (called imperative or procedural programming) to a new paradigm called declarative programming, in which the mechanics of how something is done are less important than what is done.

Procedural programming is used in the code you write; most of that is Objective-C when you are writing for Mac OS X and iOS. For most people, writing procedural code “feels” like programming. (In addition to its procedural programming concepts, Objective-C uses object-oriented programming, hence its name.)

Languages that are declarative (that is, focusing on what is done) are particularly common on the Web. Most people consider Cascading Style Sheets (CSS), regular expressions, and the basics of SQL (SELECT statements, for example) to be examples of declarative languages. Markup languages in general—including HTML itself—are declarative rather than procedural because they describe what the end result should look like. For many people, designing databases and web pages doesn’t “feel” like programming (and many people do not think that it is).

The distinction between these two programming paradigms is not a matter of good versus bad or old versus new: It is simply a contrast between two ways of developing software. As you approach Xcode, Mac OS X, and iOS, you do not have to make a choice because both paradigms are supported in Xcode. Most of the time, a specific editing function is implemented only in procedural or declarative styles because one or the other is the natural way of editing that particular set of instructions.

If you are starting building apps for Mac OS X or iOS that use Core Data, you will use descriptive editors for the Core Data side of things just as you do with many SQL-based development environments, and you will use procedural editors for the text-based code that you write to manipulate the interface and the database.

Working with Object-Oriented Programming

Object-oriented programming is now so pervasive that for many people, it is the only kind of programming they do. Instead of the simple and relatively unstructured code shown in Listing 1.1, objects are created that encapsulate data and functionality. These objects interact with one another to get the work of the program done.

When people first started using object-oriented programming techniques, some critics pointed out that it took much more code and programming time to use object-oriented techniques and languages than to use traditional techniques and languages. The idea of writing a program with the three lines shown in Listing 1.1 is unthinkable in the object-oriented programming world.

However, the arguments made by proponents of object-oriented programming and borne out by decades of experience are that

  • Object-oriented programming is easier to maintain and modify over time in part because of its inherent structures.
  • It might take many more lines to write a very simple program using object-oriented programming techniques, but as the complexity of the program increases, the incremental effort to build each new feature can be significantly less than with traditional techniques.

When you put these points together, you can see that there is a significant difference between simple and complex programs no matter whether you are using object-oriented programming or traditional programming. The benefits of object-oriented programming really only appear in complex programs, whereas the limitations of traditional programming methods do not appear in short programs.

In practical terms, this means that to learn how to use the tools of Mac OS X and iOS along with Xcode, you have to work with hefty examples. And if you try to use a simplified example, you might wind up thinking that these tools are overly complex. That is true in one sense: Using these tools to write something very simple is overkill. But not using tools like this to write complex software is frequently self-defeating.

As you begin to work with Xcode, Core Data, Mac OS X, and iOS, you will find yourself at the helm of a sophisticated and powerful development environment. In this book, you will see how to start small and build up to very complex apps. In the initial hours, because the examples are small, you may be tempted to worry about the complexity, but just remember that the complexity will pay off as the examples become more complex.

  • With that overview, you might be interested in the Tutorial “Using Xcode to Write ‘Hello, World’” in Hour 1 of Apple’s Xcode Quick Start Guide. It is 20 pages long and demonstrates precisely these points.
  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020