Xcode. Tools projects

Here are two easy and nice article for the Xcode beginners found on Me and Mark Publishing
Introduction to Xcode
Using Xcode with Unsupported Languages
Mac OS X is new OS for me. As well as Xcode is new development environment. It is a new world compare with Microsoft Windows and Visual Studio. To step in into this new dev world is much easier with these two articles.
The main idea is simple - Xcode allows to create so called Tools projects:

Tools project does not have the graphical user interface. You can build the tool project for C (Standard Tool template) and for C++ (C++ Tool). You can choose Foundation tool for Objective-C.

Xcode comes with built-in support for AppleScript, C, C++, Java, and Objective C. It is possible to create an external build system for other languages - the second link explains how to do it.