public, private, protected access modifiers in OOP

[Bol-Bacchan]

I am not a big programmer, In fact I have just started learning about the object oriented programming and I have gone through some programs written in different languages but these three words called as access modifier are used there. Now I don't get that somewhere they use public and somewhere they use private or protected. I guess there would be no difference between the private and protected. I didn't got this concept properly.

[Villiers]

For classes, it should have methods that can use any object of such a class. In our example, the init (), show () and set (). On the other hand, data should be encapsulated yes, that one can not directly access it. For these kinds of differences, there are three key words, public (on the method / attribute can be accessed from anywhere by), private (method / attribute is accessed, only the defining class must in the exactly ) and "protected `` (from the class and all derived classes can be accessed on the method / attribute). In addition, all objects must have all the features of an object class in the same class of access (including private-defined).

[Vandam]

. NET, there are five access levels. The first level of access each provides unlimited access. It is referred to as public. All defined as public classes, methods or properties are visible to any other code. The classes for ASP.NET pages, for example, be defined as public, as they are accessed on needs to display the page. The exact opposite of this public access is private. To keep the access limited to its own class. In a private defined properties or methods can be accessed only by code, the class is contained in them. From derived classes or other elements can not be accessed in private.

[Jacques25]

Between public and private, there are other access levels. The protected (protected) level allows properties and methods that are defined as protected, within their own class and all of these derived classes are visible. The next level is in VB.NET with a friend, called in C # with internal. It says that properties and methods that are defined or internal as a friend, all classes within its own assembler code can be accessed by all. This plane can be combined with protected to define properties and methods that all derived classes and all classes are available to the assembler within. It's called common or protected friend / internal, since both approaches are supported.

[Author]

Be careful not to confuse between the static keyword and access modifiers.

1. A member of a class can be:

• linked to class => static
• bound to the instance => no keyword

2. A member of a class can also be:

• visible only by the class => private
• visible to the whole package => no keyword
• visible to the whole package, and the subclasses within the heritage (*) => protected
• visible to everyone => public

[ismail12]

Hello,

1. private - Only the current class will have access to the field or method.

2. protected - Only the current class and subclasses (and sometimes also same-package classes) of this class will have access to the field or method.

3. public - Any class can refer to the field or call the method.