Elements of Computational Thinking

• Representational abstraction

  • Analysing what is relevant to a given scenario and simplifying a problem based on this information
• Abstraction enables more efficient design during software development by focusing on essential elements, reducing project time and preventing unnecessary program size
• Data abstraction

  • Hiding details about how data is being stored, allowing the use of abstract data structures without concern for implementation
• Multiple levels of abstraction

  • Used in very large, complex problems where each level performs a different role, with highest levels providing user interface and lowest levels executing machine code
• Abstraction by generalisation

  • Grouping together similarities within a problem to identify what kind of problem it is, allowing categorization and common solutions
• Abstraction

  Removing excessive details to arrive at a representation of a problem that consists of only the key features
• Programming languages can be separated into

  • High-level languages
  • Low-level languages
• Abstraction allows non-experts to make use of systems or models by hiding complex or irrelevant information
• Procedural abstraction

  • Performing functions like pushing and popping items without knowledge of the code used for implementation, used in decomposition
• Low-level languages such as assembly code and machine code directly interact with computer systems but are more difficult to write
• Assembly code, although easier to memorize, still requires programmers to know the mnemonics associated with it
• Layers of abstraction used in

  • Networking
  • Programming languages
• Assembly code and machine code


  Languages that directly interact with computer systems but are more difficult to write
• Attributes in object-oriented programming

  Abstraction for the characteristics of an object
• Assembly code


  • Easier to memorise but requires knowledge of mnemonics associated with the instruction set specific to the processor
• Devising an abstract model for a variety of situations

  Consider the problem to be solved, key features, usage, target audience, and relevance of problem parts
• Abstraction

  A simplified representation of reality
• Coding has become accessible to non-specialists due to the abstraction provided by high-level languages
• High-level languages

  • Provide an abstraction for machine code, making programming easier as syntax parallels natural language and is considerably easier to learn and use compared to low-level languages
• Object-oriented programming

  Makes use of objects as an abstraction for real-world entities, considering functionality, interface, and properties
• Methods in object-oriented programming

  Abstraction for the actions a real-world object can perform
• Inputs

  Data required to solve the problem, entered into the system by the user
• Designing a solution

  1. Thinking ahead about the different components of a problem and how they will be handled in the best way possible

  2. Considering problems or difficulties that may arise when the software is used

  3. Designing strategies to make programs easy and intuitive to use
• Preconditions are requirements that must be met before a program can be executed
• Identifying inputs and outputs for a given scenario


  Deciding on suitable data type, structure, and method to present the solution
• Preconditions can be tested for within the code or included in the documentation accompanying a subroutine, library, or program
• Outputs

  Results passed back once the inputs have been processed and the problem solved
• Specifying preconditions

  Ensuring arguments passed meet certain criteria as defined by the preconditions
• All computational problems consist of inputs which are processed to produce an output
• Caching frees up bandwidth for other tasks on a network
• Caching is the process of storing instructions or values in cache memory after they have been used, as they may be used again
• Caching is very common in the storage of web pages
• Prefetching loads and stores instructions and data in cache before they are fetched, reducing the time spent waiting for instructions to be loaded into RAM from the hard disk
• The effectiveness of caching depends on how well a caching algorithm manages the cache
• Including preconditions within the documentation reduces the length and complexity of the program as well as saving time needed to debug and maintain a longer program
• Reusable program components are often packaged into libraries for reuse
• Reusable components are more reliable than newly-coded components as they have already been tested and any bugs dealt with, saving time, money, and resources
• Compatibility issues may arise when integrating existing components developed by third parties with the rest of the software, potentially requiring modifications which can be costly and time-consuming
• Web pages that a user frequently accesses are cached to load content without any delay
• The purpose of preconditions is to ensure necessary checks are carried out before the execution of a subroutine, making subroutines more reusable