The variables you declare in Objective-C — Objective-C data types — must be a type that the compiler can recognize. Objective-C comes with a number of built-in data types, as well as mechanisms to create new ones, for programming your iOS or Mac OS X applications.
| Type | Description | Size |
|---|---|---|
| char | A character | 1 byte |
| int | An integer — a whole number | 4 bytes |
| float | Single precision floating point number | 4 bytes |
| double | Double precision floating point number | 8 bytes |
| short | A short integer | 2 bytes |
| long | A double short | 4 bytes |
| long long | A double long | 8 bytes |
| BOOL | Boolean (signed char) | 1 byte |
| Enumeration types |
<span class="code">enum typeName { identifier1, ... identifiern};</span>
Identifiers are of constants of type int.
typedef
typedef typeName identifier;
Associates an identifier with a specific type.
Constants
const type identifier = value; #define identifier value
Allows you to define names for constants.