#instance method

How to Call a Method in Java

What is a Method ? A method is a block of code that performs a particular task.  It can be invoked anywhere in a program . It increases code readability and reusability. When a compiler encounters a method name, it executes its body. After finishing the method execution, the control is sent back to the caller method’s immediate next statement.   How to Call a Method in Java ? Calling an Instance…

method type identifier로 +를 사용하는 class method는 java에서의 static method와 비슷함. identifier로 -를 사용하는 instance method는 흔히 생각하는 method.

쉽게 생각해서 class method는 구현된 메소드를 다른 클래스에서 사용하기 위해 해당 메소드가 구현된 클래스의 객체를 생성할 필요가 없는 것이고 instance method는 일반적인 메소드와 마찬가지로 해당 메소드의 클래스의 객체를 생성해야 접근할 수 있음.

Instance methods are called on the. . . wait for it. . . instance of a class, while class methods are called on the class itself.  For example:

>>> class Demo

>>>   def method_1

>>>     puts "instance method!"

>>>   end

>>>    def self.method_1

>>>      puts "class method!"  # can also be written as Demo.method_1

>>>   end

>>> end

>>> Demo.new.method_1

=> "instance method!"

>>> Demo.method_1

Objective-C:

Instance methods use an instance of a class, whereas a class method can be used with just the class name. In Objective-C they are defined thusly:

@interface MyClass : NSObject

+ (void)aClassMethod;

- (void)anInstanceMethod;

@end

They could then be used like so:

[MyClass aClassMethod];

MyClass *object = [[MyClass alloc] init];

[object anInstanceMethod];

Some real world examples of class methods are the convenience methods on many Foundation classes like NSString's +stringWithFormat: or NSArray's +arrayWithArray:. An instance method would be NSArray's -count method.

C#:

In C# a class method is marked static. Methods and properties not marked static are instance methods.

class Foo {

  public static void ClassMethod() { ... }

  public void InstanceMethod() { ... }