Objective-C

NsdictionaryImmutable dictionariesWays to create a dictionary How to create a dictionary nsdictionary *dy = [Nsdictionary dictionarywithobject:@ "a" forkey:@ "B"]; Nsdictionary *dy1 = [Nsdictionary dictionarywithobjectsandkeys:@

We know that in objective-C, using @ property with @ synthesize enables the compiler to automatically implement the getter/setter method, which is convenient to use and can be directly used.Object. Attribute. Nsstring * Name;Nsuinteger age; @

First lookCode: @ Interface Viewcontroller () {nsobject * OBJ _;} @ property (retain) nsobject * OBJ; // Note that the default value is @ property (atomic ,.... @ End @ Implementation Viewcontroller @ Synthesize OBJ = OBJ _; -( ID ) Init {

In objective-C, the real implementation of message and method is bound in the execution phase, rather than the compilation phase. The compiler converts the message to the call of the objc_msgsend method.The objc_msgsend method contains two required

From the first applicationProgramStart with helloworld: Objective-C version: # Import Foundation / Foundation. h > Int Main ( Int Argc, Const Char * Argv []) {NSAID utoreleasepool * Pool = [[NSAID utoreleasepool alloc]

Math in C language. h has a function: Double POW (double N, double M); Calculate math of C language to the power of M of N. h has a function: Double SQRT (double N); Calculate the value of the root number N (start n). The string in C: char * name = "

Structures commonly used in objective-C: nsange, nspoint, nssize (cgsize), nsrect 1 nsange The prototype of nsange is typedef struct _NSRange { NSUInteger location; NSUInteger length; } NSRange; Nsmakerange Functions Ns_inlinez is

Conversion from: instancetype and ID keyword in objective-CI. What is instancetype? The same as the ID indicates an unknown object.  2. Related Result types) According to the naming rules of cocoa, the following rules are met: 1. In the class method,

Objective-C Memory Management Summary of mutual conversion between core Foundation objects     IOS allows easy conversion between objective-C and core Foundation objects. For nsstring and cfstringref, direct conversion is free of pressure:  

The structures that are frequently used in objective-C include nsange, nspoint, nssize (cgsize), and nsrect. 1 nsange The prototype of nsange is typedef struct _NSRange { NSUInteger location; NSUInteger length; } NSRange; Nsmakerange

1. Use of random numbers 1) arc4random () is more accurate and does not need to be generated immediately. Usage: The code for getting an integer between 0 and X-1 through arc4random () is as follows: Int value = arc4random () % x; The code for