difference between nil and null

I. Brief description1.nil is used to assign values to objects (any object in objective-c is of type ID)2.NULL assigns any pointer, null and nil are not interchangeable3.nil for Class pointer assignment (in OBJECTIVE-C the class is an object and is

The problem is this.Nsdictionary *sample = [nsjsonserialization jsonobjectwithdata:received options:nsjsonreadingmutableleaves Error: &*messageinfo = [Sample objectforkey:@ "message"];Sample is a dictionary, Messsageinfo is obtained from the

We all know that nil, nil, NULL, nsnull are all empty but what is the difference, I believe that we have little attention. Today we're going to talk a little bit about the difference between these few empty1. NilNil generally refers to the empty

NIL: A null pointer to an object that assigns a null value to the objective C ID object.Nil: A null pointer to a class that represents a null value for the class.NULL: A null pointer to another type (for example, base type, C type) to assign a null

Nil: A null pointer to an Objective-c object.(#define NIL ((ID) 0))Nil represents a Objective-c object with a pointer to an emptyNil: A null pointer to an OBJECTIVE-C class.The first capital of nil and nil is a bit different, nil defines a pointer

I. Classes and objectsConcepts of classes and objects:1. A class is a highly abstract class that defines the static properties (attributes) and dynamic properties (methods) that this class of objects should have.2. An object is an instance of a

Nil, Nil, NULL, and NSNull in Objective C. nilnsnull Kenyo's original statement is: the estimation of IOS development is a headache for Objective-C's memory management mechanism. Accidentally, the program will leak memory, and I am no exception, A

1.nil >defines the ID of a null instance. Defines an instance that is empty, pointing to an empty pointer to an object in OC. > Sample code: NSString *somestring = nil; Nsurl *someurl = nil; ID someobject = nil; if (Anotherobject = = nil)//do

1.nil pointer to an object is empty the definition in objc.h is as follows:#ifndef nil# if __has_feature (cxx_nullptr) # define nil nullptr# else# define nil __darwin_null# endif#endifObject in objective-c for ID typeNSString *name = nil; Nsurl

1, nil and null from the literal meaning to understand the simpler, nil is an object, and null is a value, I understand that nil is to set the object to NULL, and NULL is the basic type is set to empty, the personal feel a bit like the attribute,