General knowledge

• Data type


  A classification of data that determines the possible values for that type, the operations that can be performed on values of that type, and the way values of that type can be stored
• Data types


  • integer
  • real/float
  • Boolean
  • character
  • string
  • date/time
  • pointer/reference
  • records (or equivalent)
  • arrays (or equivalent)
• Variables declared as a pointer or reference data type


  Used as stores for memory addresses of objects created at runtime, ie dynamically
• Not all languages support explicit pointer types, but students should have an opportunity to understand this data type
• User-defined data types


  Based on language-defined (built-in) data types
• Statement types that can be combined in programs

  • variable declaration
  • constant declaration
  • assignment
  • iteration
  • selection
  • subroutine (procedure/function)
• Definite and indefinite iteration


  Indefinite iteration with the condition(s) at the start or the end of the iterative structure
• A theoretical understanding of condition(s) at either end of an iterative structure is required, regardless of whether they are supported by the language being used
• Use nested selection and nested iteration structures
• Use meaningful identifier names and know why it is important to use them
• Arithmetic operations


  • addition
  • subtraction
  • multiplication
  • real/float division
  • integer division, including remainders
  • exponentiation
  • rounding
  • truncation
• Relational operations


  • equal to
  • not equal to
  • less than
  • greater than
  • less than or equal to
  • greater than or equal to
• Boolean operations


  • NOT
  • AND
  • OR
  • XOR
• Variable


  A named storage location that can hold a value that can change during the execution of a program
• Constant


  A named storage location that holds a value that cannot change during the execution of a program
• Advantages of using named constants
• String-handling operations


  • length
  • position
  • substring
  • concatenation
  • character → character code
  • character code → character
  • string conversion operations
• String conversion operations


  • string to integer
  • string to float
  • integer to string
  • float to string
  • date/time to string
  • string to date/time
• Be familiar with, and be able to use, random number generation
• Exception handling


  A mechanism for handling errors or unexpected situations that occur during the execution of a program
• Subroutine


  A named 'out of line' block of code that may be executed (called) by simply writing its name in a program statement
• Advantages of using subroutines in programs
• Parameters


  Used to pass data within programs
• Be able to use subroutines with interfaces
• Be able to use subroutines that return values to the calling routine
• Local variables


  Variables that exist only while the subroutine is executing and are accessible only within the subroutine
• It is good practice to use local variables
• Global variables


  Variables that are accessible throughout the entire program
• Stack frame


  Used with subroutine calls to store return addresses, parameters, and local variables
• Recursive techniques


  Programming techniques that involve a subroutine calling itself, either directly or indirectly
• Be able to solve simple problems using recursion
• Procedural-oriented programming


  A programming paradigm that emphasizes the use of procedures or subroutines to solve problems
• Be able to construct and use hierarchy charts when designing programs
• Be able to explain the advantages of the structured approach
• Concepts of object-oriented programming

  • class
  • object
  • instantiation
  • encapsulation
  • inheritance
  • aggregation
  • composition
  • polymorphism
  • overriding
• Class


  Defines methods and property/attribute fields that capture the common behaviours and characteristics of objects
• Object


  Based on a class, created using a constructor, implicit or explicit, and a reference to the object assigned to a reference variable of the class type
• Composition


  Represented by a black diamond line in the Unified Modelling Language (UML)
• Aggregation


  Represented by a white diamond line in the Unified Modelling Language (UML)
• Know why the object-oriented paradigm is used