Xcode provides everything developers need to create great applications for Mac, iPhone, and iPad. Xcode 4 has been streamlined to help you write better apps. It has unified user interface design, coding, testing, and debugging all within a single window. The Xcode IDE analyzes the details of your project to identify mistakes in both syntax and logic, it can even help fix your code for you.
Xcode runs on OS X Lion and includes the Xcode IDE, Instruments, iOS Simulator, the latest Mac OS X and iOS SDKs, and hundreds of powerful features: Innovative tools to help you create great apps
пїЅ Interface Builder is fully integrated as a design canvas within the Xcode IDE
пїЅ The Assistant shows files related to what youre editing, such as the header, superclass, or controller
пїЅ The Version editor shows a live source code comparison through Git or Subversion history
пїЅ Live Issues display errors as you type, and Fix-it can correct the mistakes for you
пїЅ Apple LLVM compiler is embedded within the IDE with support for Objective-C, C, and C++
пїЅ The new LLDB debugging engine is faster and more memory-efficient than GDB
пїЅ Instruments adds System Trace and new iOS instruments including OpenGL ES

Streamlined interface that is faster and easier to use
пїЅ Design your interface side by side with the backing source code
пїЅ Create connections from your GUI design directly to the related source code
пїЅ Use tabs to organize your workspace, or double-click to open files in a new window
пїЅ Schemes let you customize exactly how your app will build, run, profile, and deploy
пїЅ Debugging and console views slide in without disturbing your place in the editor

Professional editor keeps you focused on your code
пїЅ Click the Jump Bar at the top of the editor to instantly go to another file
пїЅ View message bubbles to see errors, warnings, and other issues right beside the code
пїЅ Use the ribbon on the left of the editor to fold your code, or highlight scope

Embedded Apple LLVM technology finds and fixes bugs for you
пїЅ Analyzer travels countless code paths looking for logical errors before they become bugs
пїЅ Live Issues underlines coding mistakes as you type with no need to build first
пїЅ Fix-it can confidently correct mistakes for you with just a keystroke
пїЅ Code completion for Objective-C, C, and C++ is incredibly fast and accurate

Instruments for visual performance analysis
пїЅ Compare CPU, disk, memory, and OpenGL performance as graphical tracks over time
пїЅ Identify performance bottlenecks then dive deep into the code to uncover the cause
пїЅ Monitor your app directly, or sample the entire system, with very little overhead

To test or deploy applications on an iOS device you must be a member of Apples iOS Developer Program. To submit your Mac or iOS apps to the App Store you must be a member of the Mac or iOS Developer Program. Some features may require Internet access.

New Features in Xcode 4.4
Scene Kit
Xcode now includes a viewer and editor for 3D files as .DAE documents.
New Interface Builder Support for AppKit Features
XcodeпїЅs Interface Builder includes support for new AppKit features like trackpad zoom support and auto-layout.

LLVM 4.0 Compiler
Xcode now includes the Apple LLVM Compiler version 4.0, including the following new Objective-C language features:
пїЅ Default @synthesize: automatically synthesizes an @property when unimplemented
пїЅ Objective-C literals: create literals for NSArray, NSDictionary, and NSNumber, just the same as the literals for NSString
пїЅ Objective-C container subscripting: use '[]' syntax to access containers such as NSArray and NSDictionary


Installation
This preview release of Xcode 4.4 is distributed as a single application bundle, Xcode.app.
Upon final release in the App Store, this will enable developers to easily download Xcode directly.
During the preview period, to install Xcode.app, double- click to open the downloaded DMG file, and drag the Xcode.app file to your Applications folder.

Within Xcode, you can launch additional developer tools, such as Instruments and FileMerge,
via the menu item Xcode > Open Developer Tool. You can then keep the tool in your Dock for access when Xcode is not running.
Not all of the tools previously included in the Xcode installer are bundled in this preview release.

This preview release includes Unix development tools for OS X 10.8 placed in /usr.
You can download these tools, now known as the Command Line Tools, from Xcode preferences.
Look for the them in the Components tab of the Downloads preferences pane.