Basic Types of Objective-C basic syntax

 

Basic data types (NSInteger, CGFloat) and C data types (int, float, double, char, etc)

// Int, or NSInteger
That is to say, when int type variables are needed, they can be the same as the program that writes C,Use int or NSIntegerBut we recommend that you use NSInteger, because you do not need to consider whether the device is 32-bit or 64-bit.
There is a special symbol in OC: "@", which roughly means "this is OC ".
The null pointer object in OC is nil, not null.

 

// CGFloat is float or double

// @ Selector is a very special type. It is a bit similar to a function pointer. You can pass a function as a parameter.
 
// NSDateDate and time.
Code for obtaining the current time: NSDate * today = [NSDate date];

// NSLog
NSLog is a function defined in the Foundation framework for character output.
NSLog automatically switches to a new line after printing. You do not need to add an extra \ n at the end of the format string.
NSString * aString = @ "Hello New York! ";
NSLog (@ "The object description is: % @", aString );