IDE for iPhone, iPad and desktop applications development on Mac

I am absolutely new to Mac world. Which IDE I can use for iPhone, iPad and 开发者_如何学Pythondesktop applications development?

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I would say Xcode.
To start using it, see, for example, Tools for iOS Development.

And don't hesitate to take a look at the iPhone Dev Center : it'll give you some useful informations about iPhone/iPad development ;-)

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Xcode is the IDE by which you make apps for iPhone,iPad and desktop..