Objective-C Where to define initial Class Properties - objective-c

Question

just wanted to ask where I define initial class properties?
From other languages I am used to define some standard properties in the head before the content of the class starts.
For example paths to files. Settings and so on.
Where I fill these initial properties with values in Objective-C?
Thanks

Answer 1

Generally it's something like:
MyClass.h:
extern NSString * const staticValue1;
extern NSString * const staticValue2;
#interface MyClass : NSObject
{
NSString *_strval;
int _intval;
float _fltval;
}
#property (retain, nonatomic, readwrite) NSString *strval;
#property (assign, nonatomic, readwrite) int intval;
#property (assign, nonatomic, readwrite) float fltval;
#end
MyClass.m:
NSString * const staticValue1 = #"Something";
NSString * const staticValue2 = #"Something else";
#interface MyClass
#synthesize strval = _strval;
#synthesize intval = _intval;
#synthesize fltval = _fltval;
- (id)init
{
self = [super init];
if (self != nil)
{
[self setStrval:[NSString stringWithFormat:#"This is a %#", #"string"]];
[self setIntval:10];
[self setFltval:123.45f];
}
return self;
}
- (void)dealloc
{
[self setStrval:nil];
[super dealloc];
}
#end
This demonstrates the use of synthesized properties which are being used here to manage the memory of the instance variable _strval, which requires retaining/releasing to avoid memory leaks. Note that [self setStrval] is initialised with an autoreleased object (from [NSString stringWithFormat) and will be retained by the setter method. Alternatively these methods can be called using the following syntax, if you prefer:
self.strval = [NSString stringWithFormat:#"This is a %#", #"string"];
self.intval = 10;
self.fltval = 123.45f;

Answer 2

Maybe some of what you are after can be implemented with class methods.
Class methods are coded with a + (instead of the instance methods' -), and can't refer to instance variables, as they are not associated with any specific instance of the class.
This is a class method to return a default string:
+ (NSString *)myDefaultString
{
return #"Some default value";
}
You call it by simply calling it with the class name at the receiver's place. Imagine you have defined the method in a class called MyClass, the you call it like this:
NSString *str = [MyClass myDefaultString];
You'll notice that there is no alloc/init calls in this.

Answer 3

Public property needs to be define in .h file.
#interface MyClass {
}
#property(nonatomic, reatin) NSString *a;//Define as per needs, then synthesise in .m file
#end
For private property you need define inline category in .m file-
#interface MyClass ()
#property(nonatomic, reatin) NSString *b;//Define as per needs, then synthesise in .m file
#end
#implementation MyClass
#synthesize a = _a;
#synthesize b = _b;
- (void)viewDidLoad {
//You can initialise property here or in init method
self.a = #"Demo1";
self.b = #"Demo2";
}
//Now you can have other code for this class.
#end