Objects are defined in classes and therefore these two terms are often used interchangeably. Each object is actually an instance of a class.
Creating A Class Object
NSMutableArray *arrayInstance = [[NSMutableArray alloc] init;
‘alloc’ allocates the memory for the object and ‘init’ initialises it.
Instance Methods
Sent to instances of the class (objects).
Calling:
//Simple method call:
[MyObject1 SomeMethod:ArgumentForMethod];
//Calling a method with multiple arguments:
[MyObject1 SomeMethod:ArgumentForMethod
NameOfAnArgument:Argument
NameOfAnArgument:Argument];
Class Methods
Sent to class itself (to create new instances of the class or retreive soem global property).
Destroy An Object
[MyObject1 release]; //Destroy the object
MyObject1 = nil; //Ensure the pointer to the object (that no longer exists) can't be accidentally used