Dark Horse Programmer---iOS learning log 11

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1, facing the

Object-oriented Oo, there is no unified concept, broadly defined as: according to people to understand the objective world of system thinking mode, the use of object-based (entity) concept to establish a model, simulation of the objective world analysis, design, implementation of software methods. Through the object-oriented concept, the computer software system can correspond with the real-world system one by one.

Advantages: Greatly improve the success rate of software projects

Reduced maintenance costs

Increased portability and reliability

Object-oriented three main features:

Encapsulation of

Polymorphism

Inheritance of

2. Classes and objects

A class is a collection of entities with similar internal states and motion laws.

Object refers to a variety of entities in the real world, it can refer to specific things can also refer to abstract things.

The method of abstracting things from everyday life into classes: the extraction of nouns

The definition of a class in OC has two parts: the declaration of the class and the implementation of the class.

Class declarations use keywords: @interface and @end

Class implementations use keywords: @implementation and @end

The Declaration and implementation of a method must begin with a + or-

+ denotes class method (static method)

-Represents an object method (dynamic method)

There are 3 common scope of member variables:

@public can be accessed globally

@protected can only be accessed within the class and within subclasses

@private can only be accessed within the class

Declaration implementation syntax for a class

Statement:

@interface Class Name: Parent class name

{

Class properties

}

Class behavior

@end

Realize:

@implementation class Name

Class properties

@end

Dark Horse Programmer---iOS learning log 11