What is instancetype?
instancetype is a contextual keyword that can be used as a result type to signal that a method returns a related result type. For example: @interface Person + (instancetype)personWithName:(NSString *)name; @end. instancetype , unlike id , can only be used as the result type in a method declaration.
What is init () in Java?
The term init() is a method name in Java. The name is followed by Java code within { and }. A method has a name, such as init, and parentheses, such as ( ). The init() method has no arguments inside the parentheses. That means that no data are passed to the init() method.
What is instancetype in Objective-C?
Use the instancetype keyword as the return type of methods that return an instance of the class they are called on (or a subclass of that class). These methods include alloc , init , and class factory methods. Using instancetype instead of id in appropriate places improves type safety in your Objective-C code.
What is init Swift?
Swift init() Initialization is the process of preparing an instance of a class, structure, or enumeration for use. This process involves setting an initial value for each stored property on that instance and performing any other setup or initialization that is required before the new instance is ready for use.
What is Typedef Objective-C?
The Objective-C programming language provides a keyword called typedef, which you can use to give a type a new name. Following is an example to define a term BYTE for one-byte numbers −
Is Objective-C object-oriented?
About Objective-C. Objective-C is the primary programming language you use when writing software for OS X and iOS. It’s a superset of the C programming language and provides object-oriented capabilities and a dynamic runtime.
What is Init method used for?
Init method is a predefined method to initialize an object after its creation. Init method is a life cycle method for servlets for java. It is started by the browser when java program is loaded and run by the browser. Init method is a predefine method to initialize an object after its creation.
What is true Init method?
The init method is designed to be called only once. It is called when the servlet is first created, and not called again for each user request. It simply creates or loads some data that will be used throughout the life of the servlet. A – The service() method is called when the servlet is first created.
Why INIT is used in Swift?
Unlike Objective-C initializers, Swift initializers don’t return a value. Their primary role is to ensure that new instances of a type are correctly initialized before they’re used for the first time.
What is the difference between VAR and let in Swift?
What is the difference between them ? Both let and var are for creating variables in Swift. let helps you create immutable variables (constants) while on the other hand var creates mutable variables.
Why don’t we use strong for enum property in Objective-C?
We don’t use strong for enum property in Objective-C because enums aren’t objects so we can ‘t specify them as strong or weak.
When to use instancetype as a result type?
instancetype is a contextual keyword that can be used as a result type to signal that a method returns a related result type. For example: @interface Person + (instancetype)personWithName:(NSString *)name; @end. instancetype, unlike id, can only be used as the result type in a method declaration.
When to use instancetype instead of ID in Objective C?
Using instancetype instead of id in appropriate places improves type safety in your Objective-C code. For example, consider the following code: Because of the instancetype return type of +factoryMethodA, the type of that message expression is MyObject *. Since MyObject doesn’t have a -count method, the compiler gives a warning about the x line:
How to write an init method in Swift?
I want to write an init method in Swift. Here I initialize an NSObject class in Objective-C:
How to disable init to force the use of a designated initializer?
In case you intend to disable init to force the use of a designated initializer, there is an attribute for that: This generates a warning unless any other initializer method calls myOwnInit internally. Details will be published in Adopting Modern Objective-C after next Xcode release (I guess).