[OC Fourth day] "mastering" 03-self used in Object methods

"Mastering" 03-self used in Object methods

Self refers to the object that invokes the current object's method.

Once again, the code will understand.

"Mastering" 04-self used in class methods

The essence of [P class] Return is the current class (class object)

[Self Run]

"Understanding" 05-self modifier variables

Self->speed = speed;

Local variables temporarily mask the scope   of global variables if they have the same name int Ten ;    A  = A;

    Self-> speed accesses a local variable that is accessed by the instance variable plus self after the instance variable of the    class is    not added to the self.

"Mastering" 08-Inherited code implementation

  Bigyellowdog itself (the actual definition) does not eat and run behavior,  but the Bigyellowdog parent class Dog has  so, Bigyellowdog also have, because inherited

The inheritance format is marvelous

@interface Dog:animal

"Mastering" 11-instance variable modifier introduction

    @public        Public, the @private private can be accessed anywhere through an instance        object       , indicating that only @protected protected type can be used in the current class    , indicating access only in the current class and subclass

"Mastering" The effects of 12-instance variable modifiers on subclasses

Interview question:    @private types of variables, can the quilt class inherit?    subclasses can inherit all the instance variables and methods of the parent class    However, not all of them can access        @private type of variable, can the quilt class access?    Cannot access

"Mastering" The private variables in the 13-OC

Person.m

" Person.h " // defining instance variables in. m ///Pure private variable, which can only be used in the current class, cannot be inherited by the quilt class, and cannot be accessed int m = ; @implementationperson-(void) run{    NSLog (@ " people walking, speed is%d"  , M);} -(void) eat{    NSLog (@ "eat:m =%d", M);} @end

"Mastering" private Methods in 14-oc

. h file, which can be seen as an external interface

Private methods are not declared but implemented    only in their own class class [self private Method] Access

Private method (relative private) cannot inherit from quilt class

It's simple, but you can watch the video again.

Introduction and rewriting of "mastery" 15-description method

When weprint object D in the format of% @, when the object's description method object is called, if the description method of the parent class is not overridden, the

This should be more important, this one, it's pretty detailed.

return [NSString stringWithFormat:@ " Age:%d, color:%d", _age,_color];

   // Print class information        in the form of%@ NSLog (@ "class");

"Mastering" the implementation of 16-polymorphic

Polymorphic nature needs to go deep into memory, but there are limitations, such as you think about how the parent class can use subclasses, because memory has this method

The parent class cannot use the subclass's unique method, because it is the compile check, a check the parent class without this method directly error, only downward transformation

[OC Fourth day] "mastering" 03-self used in Object methods