OC learning 01-class and Object

OC learning 01-class and Object
Object-Oriented Programming

Basic:

Concept: object class encapsulation polymorphism main languages include C ++, Java, OC

Differences between process-oriented and object-oriented

	Process-oriented	Object-oriented
Features	Analysis Steps to implement functions	Analyze the problem and find out the involved objects and their functions
Focus	Implement Functions	Object Design (specific function)
Example	C Language	OC, C ++, java

Basic code:

// OC print NSLog (@ Lanou); // NSInteger, CGFloat float, NSString NSInteger I = 100; NSLog (@ I = % ld, I ); CGFloat f = 3.14; NSLog (@ f = % g, f); // The OC string can contain the Chinese NSString * str = @; NSLog (@ % @, str ); // OC array // just like for loop traversal, you can directly use NSLog to traverse NSArray * arr = @ [@ 1, @ 2, @ 3]; NSLog (@ % @, arr); for (NSInteger I = 0; I <3; I ++) {NSLog (@%@, arr [I]);}

Class and object class and object are the core classes of object-oriented programming. Abstract objects with the same features and behavior are class instances. Classes are the types of objects. class definitions in OC are first defined. class, create an object and define the object in two parts. The interface and implementation (note separate writing) file :. h is the interface file ,. m is the implementation file
Interface

@interface Student : NSObject@end

Implementation

// Corresponding implementation file @ implementation Student

Create an object any object occupies space. Create an object in two steps.
① Allocate space ② initialize

// 1. allocate space Student * stu = [Student alloc]; // 2. initialize stu = [stu init]; // combine the previous two steps into a statement Student * stu = [[Student alloc] init];

Self returned during initialization refers to the self returned after completion.

-(Id) init {_ stuName = @; _ stuSex = @ female; _ stuholobby = @ male; _ stuAge = 20; _ stuScore = 100; return self ;}

Objects used

    Student *stu = [[Student alloc] init];    [stu sayHi];

Only a small number of settings are made when instance variables are initialized. the visibility of instance variables can be improved in the future.
@ Public @ private @ protected

@ Interface Student: NSObject {// visibility of member variables @ public // member variables, or instance variable NSString * _ stuName; // name NSInteger _ stuAge; // age NSString * _ stuSex; // gender CGFloat _ stuScore; // score NSString * _ stuholobby; // hobby} @ end

Operation Member

// Operation member variable // The NSLog (@ % ld, stu-> _ stuAge) of the member variable is accessed through-> ); // modify the age stu-> _ stuAge = 100; NSLog (@ % ld, stu-> _ stuAge); // modify the name, directly change the string to stu-> _ stuName = @; NSLog (@ % @, stu-> _ stuName );

Note: For public modified instance variables, you can directly use "->" to access

Some code

Main. m

Int main (int argc, const char * argv []) {// creates an object through the mobile phone class, modify the MobilePhone * mPhone = [[MobilePhone alloc] init]; mPhone-> _ phoneBrand = @ samsung; mPhone-> _ phoneColor = @ white; mPhone-> _ phoneModel = @ NAS; mPhone-> _ phonePrice = 4800; mPhone-> _ phoneSize = 1080; NSLog (@ brand: % @, color: % @, model: % @, price: % ld, screen: % ld, mPhone-> _ phoneBrand, mPhone-> _ phoneColor, mPhone-> _ phoneModel, mPhone-> _ phonePrice, mPhone-> _ phoneSize); return 0 ;}

MobilePhone. h

@ Interface MobilePhone: NSObject {@ public NSString * _ phoneBrand; NSString * _ phoneModel; NSInteger _ phoneSize; NSString * _ phoneColor; NSInteger _ phonePrice;}-(void) buyPhone; -(void) call;-(void) sendMessage;-(void) surfInternet;-(void) watchVideo; // write a function to print all information-(void) sayHi; @ end

MobilePhone. m

@ Implementation MobilePhone-(void) buyPhone {NSLog (@ bought a mobile phone);}-(void) call {NSLog (@ called);}-(void) sendMessage {NSLog (@ sent a text message);}-(void) surfInternet {NSLog (@ posted on the network);}-(void) watchVideo {NSLog (@ watched a video);} // call the initialization method-(id) init {_ phoneBrand = @ Apple; _ phoneColor = @ red; _ phoneModel = @ S5; _ phonePrice = 4000; _ phoneSize = 1080; return self;}-(void) sayHi {NSLog (@ % @, % ld, % ld, _ phoneBrand, _ phoneColor, _ phoneModel, _ phonePrice, _ phoneSize );}

The article summarizes the basic content of today's Learning