Beginner Learning iOS

The difference between @interface and @property declaration variables in Object-c objective-c language keywords, used with @synthesize pairing. xcode4.5and later versions, @synthesize can omit the function: Let the compiler automatically write a method declaration with the same name as the data member, eliminating the declaration of the read-write method.

What is the difference between these two ways?

1. If you define variables only in @interface, the variables you define can only be accessed in the current class, not in other classes, and variables declared with @property may be accessed externally.

2. Using @property to declare variables, you can use the "self. Variable name" method to read and write variables. And the way to use @interface is not possible.

It is common to define a variable in @interface brackets and repeat it with @property, which is not actually necessary. It is enough to use @property and @synthszie, because a variable is created when a read-write method of this property is synthesized with @synthsize.

Http://www.cnblogs.com/letmefly/archive/2012/07/20/2601338.html

@interface: An interface that provides a public description of the class, which contains the required information to use the class, and, after compiling this part, can use the object and invoke the class method.

@implementation: Implementation, tells the compiler how to make the class work, implements the method declared in the interface.

The code is divided into two parts, interface and implementation,

The interface section contains: @interface directives, common struct definitions, enum constants, @defines and extern global variables, and so on.
Implement partial inclusions: @implementation directives, definitions of global variables, private structs, and so on.

#import: Import Header File: Header file contains element declarations (such as struct, symbol constants, function prototypes, etc.), #import同c语言中的 # include similar, the difference is that in C, you typically use the #ifdef command to avoid a header file that contains another file, and # Impurt can guarantee that header files are included only once.

The angle bracket statement is used to import the system header file (read-only), and the quoted statement is used to import the project local header file (readable).