Abstraction in its many forms is a fundamental concept used in computational thinking and problem solving

Removing irrelevant details allows the computer scientist to focus on the essence of a problem

Data abstraction is used to create and manipulate complex data structures

Abstraction is Representation of the real world but hiding certain details. The London                      underground maps is a good example of information hiding as the                              tracks are not exact and neither is the location of the stations. It has                              removed unnecessary details that would only create confusion.this is                            called information hiding.

                     Games are also abstract , they try to represent certain aspects of the                          real world but also take out all the so many little details that would                                make it so complicated (simplify it).E.g. raising children in Sims would                            take maybe 5 steps which we know there is a lot more to do.

Problem abstraction - removing details until the problem reduces to one which has already been solved.

Automation – in this context refers to building models of real work objects in order to solve a particular problem Computer scientists have to decide what details are relevant to the problem and discard everything else

Algorithms and data structures can then be designed to solve the problem the algorithm is then implemented in program code and executed

Google moon abstractions

http://www.google.com/moon/ - shows abstraction

It is 2d representation of the moon and the moon isn’t 2d therefore it has been abstracted as making it 3d would require too much data

Landing sites have detailed imaging surrounding them, while the rest of the moon has lower resolution images. The lower resolution images have been 'abstracted'

Decomposition

•      Procedural decomposition means breaking a problem into a number of sub-problems, so that each sub-problem accomplishes an identifiable task

•      The sub-problems may themselves be further subdivided

Composition is the opposite

·         combining procedures to form a compound procedure

·         Combining data objects to form compound data objects such as a tree or stack (which you will study next year)

Procedural abstraction is used to keep the actual values used in a computation separate from the overall design

Functional abstraction

•      When you call a function to calculate a square root, or generate a random number, for example, abstraction is taken one stage further

•      Using a function does not require you to know anything about how the computation is carried out

•      You simply have to know how to call the function and what parameters to pass

Data Abstraction

The data or information that is relevant to solving a problem may be in the form of an abstract data structure such as an array, stack or queue

It could be implemented as an array and a pointer to the top of the stack – items do not need to be actually removed from the array or sorted within it