Objective-C Fundamentals

52 CHAPTER 2 Data types, variables, and constants
Let’s put some of the concepts you’ve learned in this chapter into practice by completing
the remaining tasks required to get the Rental Manager application to display
details about the set of rental properties in your portfolio.
2.5 Completing Rental Manager v1.0, App Store here we come!
Now that you have a well-rounded understanding of how data can be stored in an
Objective-C application and of the different data types involved, you’re ready to get
back to the Rental Manager application.
You may remember that when you left it earlier in the chapter, it was displaying a
list of 25 rental properties, but each property was labeled “Rental Property x.” This
didn’t provide you with much detail about each property! You now have the knowledge
and skills required to resolve this problem.
The first step is to define the information you would like to associate with each
rental property. Some good details to start with could be
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The physical address of the property
The cost to rent the property per week
The type of property (townhouse, unit, or mansion)
To store this information, you can define a custom data type based on a structure.
Open up the RootViewController.h header file for editing and insert the definitions
found in the following listing at the bottom of the file’s existing content.
Listing 2.3
RootViewController.h
typedef enum PropertyType {
Unit,
TownHouse,
Mansion
} PropertyType;
typedef struct {
NSString *address;
PropertyType type;
double weeklyRentalPrice;
} RentalProperty;
The first addition is the definition of an enumeration called PropertyType. It’s used
to group the rental properties you manage into three distinct categories: units in a
larger property, townhouses, or mansions.
The second addition is a custom data type called RentalProperty that nicely
encapsulates all of the details you want to store about a rental property. This typedef
statement declares that the RentalProperty data type is a structure containing individual
address, property type, and weekly rental price fields. If you pay close attention,
you’ll notice there’s no name specified after the struct keyword. When using a
typedef, it isn’t strictly necessary to name the struct because you usually don’t
intend people to refer to the data type in this manner but via the name assigned to it
with the typedef.