Abstraction VS Information Hiding VS Encapsulation

Go to the source! Grady Booch says (in Object Oriented Analysis and Design, page 49, second edition):

Abstraction and encapsulation are complementary concepts: abstraction focuses on the observable behavior of an object... encapsulation focuses upon the implementation that gives rise to this behavior... encapsulation is most often achieved through information hiding, which is the process of hiding all of the secrets of object that do not contribute to its essential characteristics.

In other words: abstraction = the object externally; encapsulation (achieved through information hiding) = the object internally,

Example: In the .NET Framework, the System.Text.StringBuilder class provides an abstraction over a string buffer. This buffer abstraction lets you work with the buffer without regard for its implementation. Thus, you're able to append strings to the buffer without regard for how the StringBuilder internally keeps track of things such the pointer to the buffer and managing memory when the buffer gets full (which it does with encapsulation via information hiding).

rp

The meaning of abstraction given by the Oxford English Dictionary (OED) closest to the meaning intended here is 'The act of separating in thought'. A better definition might be 'Representing the essential features of something without including background or inessential detail.'

Information hiding is the principle that users of a software component (such as a class) need to know only the essential details of how to initialize and access the component, and do not need to know the details of the implementation.

Edit: I seems to me that abstraction is the process of deciding which parts of the implementation that should be hidden.

So its not abstraction VERSUS information hiding. It's information hiding VIA abstraction.

Abstraction is hiding details of implementation as you put it.

You abstract something to a high enough point that you'll only have to do something very simple to perform an action.

Information hiding is hiding implementation details. Programming is hard. You can have a lot of things to deal with and handle. There can be variables you want/need to keep very close track of. Hiding information ensures that no one accidentally breaks something by using a variable or method you exposed publicly.

These 2 concepts are very closely tied together in object-oriented programming.

In very short

Encapsulation:– Information hiding

Abstraction :– Implementation hiding

Abstraction lets you focus on what the object does while Encapsulation means how an object works

See Joel's post on the Law of Leaky Abstractions

JoelOnsoftware

Basically, abstracting gives you the freedom of thinking of higher level concepts. A non-programming analogy is that most of us do not know where our food comes from, or how it is produced, but the fact that we (usually) don't have to worry about it frees us up to do other things, like programming.

As for information hiding, I agree with jamting.

It's worth noting these terms have standardized, IEEE definitions, which can be searched at https://pascal.computer.org/.

abstraction

1. view of an object that focuses on the information relevant to a particular purpose and ignores the remainder of the information
2. process of formulating a view
3. process of suppressing irrelevant detail to establish a simplified model, or the result of that process

information hiding

1. software development technique in which each module's interfaces reveal as little as possible about the module's inner workings and other modules are prevented from using information about the module that is not in the module's interface specification
2. containment of a design or implementation decision in a single module so that the decision is hidden from other modules

encapsulation

1. software development technique that consists of isolating a system function or a set of data and operations on those data within a module and providing precise specifications for the module
2. concept that access to the names, meanings, and values of the responsibilities of a class is entirely separated from access to their realization
3. idea that a module has an outside that is distinct from its inside, that it has an external interface and an internal implementation

Abstraction allows you to treat a complex process as a simple process. For example, the standard "file" abstraction treats files as a contiguous array of bytes. The user/developer does not even have to think about issues of clusters and fragmentation. (Abstraction normally appears as classes or subroutines.)

Information hiding is about protecting your abstractions from malicious/incompetent users. By restricting control of some state (hard drive allocations, for example) to the original developer, huge amounts of error handling becomes redundant. If nobody else besides the file system driver can write to the hard drive, then the file system driver knows exactly what has been written to the hard drive and where. (The usual manifestation of this concept is private and protected keywords in OO languages.)

Both Abstraction and Encapsulation are two of the four basic OOP concepts which allow you to model real-world things into objects so that you can implement them in your program and code. Many beginners get confused between Abstraction and Encapsulation because they both look very similar. If you ask someone what is Abstraction, he will tell that it's an OOP concept which focuses on relevant information by hiding unnecessary detail, and when you ask about Encapsulation, many will tell that it's another OOP concept which hides data from outside world. The definitions are not wrong as both Abstraction and Encapsulation does hide something, but the key difference is on intent.

Abstraction hides complexity by giving you a more abstract picture, a sort of 10,000 feet view, while Encapsulation hides internal working so that you can change it later. In other words, Abstraction hides details at the design level, while Encapsulation hides details at the implementation level.

Encapsulation- enforcing access to the internal data in a controlled manner or preventing members from being accessed directly.

Abstraction- Hiding the implementation details of certain methods is known as abstraction

Let's understand with the help of an example:-

class Rectangle
{
private int length;
private int breadth;// see the word private that means they cant be accesed from 
outside world.
 //now to make them accessed indirectly define getters and setters methods
void setLength(int length)
{  
// we are adding this condition to prevent users to make any irrelevent changes 
  that is why we have made length private so that they should be set according to 
   certain restrictions
if(length!=0)
{
 this.length=length
 }
void getLength()
{
 return length;
 }
 // same do for breadth
}

now for abstraction define a method that can only be accessed and user doesnt know what is the body of the method and how it is working Let's consider the above example, we can define a method area which calculates the area of the rectangle.

 public int area()
 {
  return length*breadth;
 }

Now, whenever a user uses the above method he will just get the area not the way how it is calculated. We can consider an example of println() method we just know that it is used for printing and we don't know how it prints the data. I have written a blog in detail you can see the below link for more info abstraction vs encapsulation