In this section, you are going to experiment with standard types in an Xcode playground. A playground lets you write code and see the results without the overhead of manually running an application and checking the output.
From Xcode’s window, select File → New → Playground.... You can accept the default name for this file; you will only be here briefly. Make sure the platform is OS X.
Figure 2.2 Configuring a playground
Click Next and save this file where you saved the RandomPassword project that you created in Chapter 1.
When the file opens, notice that the playground is divided into two sections: ...