Objective-C - iOS Programming: The Big Nerd Ranch Guide - page 59

Figure 2.10 Choosing a superclass
A panel will drop down that prompts you to create the files for this new class ( Fig-
ure 2.11 ) . When creating a new class for a project, you want to save the files that describe
it inside the project's source directory on the filesystem. By default, the current project
directory is already selected for you. You can also choose the group in the project navigat-
or that these files will be added to. Because these groups are simply for organizing and be-
cause this project is very small, just stick with the default. Make sure the checkbox is se-
lected for the RandomPossessions target. This ensures that this class will be compiled
when the RandomPossessions project is built. Click Create .
Figure 2.11 Saving class files