Computational Thinking and Programming (WJEC)
This unit involves various essential topics in computer science from problem-solving strategies to algorithms and programming constructs, exploring programming languages, data structures, data types, and the critical aspects of security and authentication.
Problem-Solving
Programmers Need to Understand the Problem
Write programs only if they understand the problem.
Develop good computational thinking skills.
Break problems into manageable chunks.
Simplify the situation.
Computational Thinking
Represent problems as steps (algorithms).
Decomposition
Break down a large problem into smaller sub-problems.
Each sub-problem can be solved independently.
Different people can work on different sub-problems.
Solutions to sub-problems combine to solve the whole problem.
Abstraction
Reduce a problem to its simplest characteristics.
Focus on the most important aspects.
Variables
Store data that can change.
Given identifiers reflecting the data stored (e.g., txt_FirstName).
Types of Variables
Local Variables: Defined within a specific function or block.
Global Variables: Accessible throughout the program.
Static Variables: Retain their value between function calls.
Dynamic Variables: Memory allocation can change during runtime.
Constants
Store data that does not change.
Given self-documenting identifiers (e.g., PI = 3.14).
Modularization
Structure programs into modular parts with clear, well-documented interfaces.
Ensure modules are independent and reusable.
Algorithms and Sorting
Algorithms Set of instructions to solve a problem.
Must be clear and ordered.
Should be language-independent (pseudo code or flowcharts).
Finite, well-defined, and effective.
Pseudo Code and Flowcharts
Pseudo Code: Instructions in plain English.
Flowcharts: Diagrams showing step-by-step instructions.
Sorting
There are many different types of search and sort algorithms that help you traverse through code and help you code faster and more efficiently
Merge Sort: Divide list into halves and recursively sort and merge.
Bubble sort: compare and swap items
Searching
Linear Search: Sequentially compare each item
Binary Search: Repeatedly divide list and compare middle item
Algorithms and Programming Constructs
Programming Constructs
Subroutines: Functions or procedures that perform a specific task.
Sequence: Execution of statements in a linear order.
Selection: Decision-making using conditional statements (if-else).
Iteration: Repeating a block of code (loops).
Counts and Rogue Values
Counts: Variables used to count occurrences or iterations.
Rogue Values: Special values that signal the end of a list or dataset.
Object-Oriented Constructs
Classes and Objects: Define blueprints (classes) and create instances (objects).
Encapsulation: Keep data and methods safe within a class.
Inheritance: Derive new classes from existing ones.
Polymorphism: Use a single interface to represent different data types.
Input, Processing, Output
Input: Data received from users or external sources.
Processing: Operations performed on data.
Output: Result of processing, presented to users.
String Handling
Use routines like concatenation, substring, and length calculations.
Mathematical Operations
Include addition, subtraction, multiplication, division, modulus, and exponentiation.
Logical Operations
AND, OR, NOT, XOR: Used in decision-making and control flow.
Importance of Testing
Ensures the program works as expected.
Identifies and fixes bugs before deployment.
Improves program reliability and performance.
Types of Testing and Evaluation
Unit Testing:
Tests individual components or functions of the program.
Ensures each part works correctly in isolation.
Integration Testing:
Tests how different components or functions work together.
Ensures integrated parts function correctly as a whole.
System Testing:
Tests the entire system as a whole.
Ensures the complete program meets the specified requirements.
Acceptance Testing:
Conducted by end-users.
Ensures the program meets their needs and requirements.
Regression Testing:
Ensures new changes or additions do not break existing functionality.
Re-runs previous tests to check for new bugs.
Evaluation
Assess how well an algorithm or program meets requirements.
Use logical reasoning and test data to determine efficiency.
Programming Languages
Markup Languages (HTML)
Design and structure web pages using HTML elements (tags).
Object-Oriented Languages (Java)
Greenfoot Environment: Utilize Greenfoot to create and manipulate objects and worlds.
Implement various concepts like inheritance, encapsulation, and polymorphism.
Assembly Language
Low-level programming with specific mnemonics for operations.
Data Structures and Data Types
Implementing Data Structures
Arrays: Use one-dimensional and two-dimensional arrays for storing elements.
Files and Records: Organize data into structured formats.
Implementing Data Types
Use data types such as integer, Boolean, real, character, and string.
Variables and Constants
Describe scope (local/global) and lifetime in programs.
Security and Authentication
Security Techniques
Use validation and authentication to secure programs.
Implement measures to protect data and prevent unauthorized access.
Program Maintenance
Corrective Maintenance: Fixing bugs found after the program is deployed.
Adaptive Maintenance: Updating the program to work with new hardware or software.
Perfective Maintenance: Enhancing the program's features and performance.
Preventive Maintenance: Making changes to prevent future problems.
Documentation
User Documentation: Instructions and guides for end-users on how to use the program.
Technical Documentation: Detailed information for developers on how the program works, including code comments, design documents, and technical specifications.
Version Control
Keeps track of changes made to the program.
Helps manage multiple versions of the program.
Allows collaboration among multiple developers.
Common tools: Git, SVN.
Code Review
Regularly reviewing code with peers.
Helps catch bugs early and improves code quality.
Encourages sharing of knowledge and best practices among developers.
This unit involves various essential topics in computer science from problem-solving strategies to algorithms and programming constructs, exploring programming languages, data structures, data types, and the critical aspects of security and authentication.
Problem-Solving
Programmers Need to Understand the Problem
Write programs only if they understand the problem.
Develop good computational thinking skills.
Break problems into manageable chunks.
Simplify the situation.
Computational Thinking
Represent problems as steps (algorithms).
Decomposition
Break down a large problem into smaller sub-problems.
Each sub-problem can be solved independently.
Different people can work on different sub-problems.
Solutions to sub-problems combine to solve the whole problem.
Abstraction
Reduce a problem to its simplest characteristics.
Focus on the most important aspects.
Variables
Store data that can change.
Given identifiers reflecting the data stored (e.g., txt_FirstName).
Types of Variables
Local Variables: Defined within a specific function or block.
Global Variables: Accessible throughout the program.
Static Variables: Retain their value between function calls.
Dynamic Variables: Memory allocation can change during runtime.
Constants
Store data that does not change.
Given self-documenting identifiers (e.g., PI = 3.14).
Modularization
Structure programs into modular parts with clear, well-documented interfaces.
Ensure modules are independent and reusable.
Algorithms and Sorting
Algorithms Set of instructions to solve a problem.
Must be clear and ordered.
Should be language-independent (pseudo code or flowcharts).
Finite, well-defined, and effective.
Pseudo Code and Flowcharts
Pseudo Code: Instructions in plain English.
Flowcharts: Diagrams showing step-by-step instructions.
Sorting
There are many different types of search and sort algorithms that help you traverse through code and help you code faster and more efficiently
Merge Sort: Divide list into halves and recursively sort and merge.
Bubble sort: compare and swap items
Searching
Linear Search: Sequentially compare each item
Binary Search: Repeatedly divide list and compare middle item
Algorithms and Programming Constructs
Programming Constructs
Subroutines: Functions or procedures that perform a specific task.
Sequence: Execution of statements in a linear order.
Selection: Decision-making using conditional statements (if-else).
Iteration: Repeating a block of code (loops).
Counts and Rogue Values
Counts: Variables used to count occurrences or iterations.
Rogue Values: Special values that signal the end of a list or dataset.
Object-Oriented Constructs
Classes and Objects: Define blueprints (classes) and create instances (objects).
Encapsulation: Keep data and methods safe within a class.
Inheritance: Derive new classes from existing ones.
Polymorphism: Use a single interface to represent different data types.
Input, Processing, Output
Input: Data received from users or external sources.
Processing: Operations performed on data.
Output: Result of processing, presented to users.
String Handling
Use routines like concatenation, substring, and length calculations.
Mathematical Operations
Include addition, subtraction, multiplication, division, modulus, and exponentiation.
Logical Operations
AND, OR, NOT, XOR: Used in decision-making and control flow.
Importance of Testing
Ensures the program works as expected.
Identifies and fixes bugs before deployment.
Improves program reliability and performance.
Types of Testing and Evaluation
Unit Testing:
Tests individual components or functions of the program.
Ensures each part works correctly in isolation.
Integration Testing:
Tests how different components or functions work together.
Ensures integrated parts function correctly as a whole.
System Testing:
Tests the entire system as a whole.
Ensures the complete program meets the specified requirements.
Acceptance Testing:
Conducted by end-users.
Ensures the program meets their needs and requirements.
Regression Testing:
Ensures new changes or additions do not break existing functionality.
Re-runs previous tests to check for new bugs.
Evaluation
Assess how well an algorithm or program meets requirements.
Use logical reasoning and test data to determine efficiency.
Programming Languages
Markup Languages (HTML)
Design and structure web pages using HTML elements (tags).
Object-Oriented Languages (Java)
Greenfoot Environment: Utilize Greenfoot to create and manipulate objects and worlds.
Implement various concepts like inheritance, encapsulation, and polymorphism.
Assembly Language
Low-level programming with specific mnemonics for operations.
Data Structures and Data Types
Implementing Data Structures
Arrays: Use one-dimensional and two-dimensional arrays for storing elements.
Files and Records: Organize data into structured formats.
Implementing Data Types
Use data types such as integer, Boolean, real, character, and string.
Variables and Constants
Describe scope (local/global) and lifetime in programs.
Security and Authentication
Security Techniques
Use validation and authentication to secure programs.
Implement measures to protect data and prevent unauthorized access.
Program Maintenance
Corrective Maintenance: Fixing bugs found after the program is deployed.
Adaptive Maintenance: Updating the program to work with new hardware or software.
Perfective Maintenance: Enhancing the program's features and performance.
Preventive Maintenance: Making changes to prevent future problems.
Documentation
User Documentation: Instructions and guides for end-users on how to use the program.
Technical Documentation: Detailed information for developers on how the program works, including code comments, design documents, and technical specifications.
Version Control
Keeps track of changes made to the program.
Helps manage multiple versions of the program.
Allows collaboration among multiple developers.
Common tools: Git, SVN.
Code Review
Regularly reviewing code with peers.
Helps catch bugs early and improves code quality.
Encourages sharing of knowledge and best practices among developers.
