2.2.1: programming techniques

• Name the three programming constructs

  Sequence, branching and iteration
• Which two categories of loop is iteration split up into?

  • Count-controlled
  • Condition-controlled
• Describe how the branching programming construct works

  A certain block of code is run if a specific condition is met, using IF statements.
• What is recursion?


  A programming construct in which a subroutine calls itself during its execution until the stopping condition is met.
• What is the base case in recursion?

  A condition that must be met in order for the recursion to end.
• State two advantages of recursion

  • Can be represented in fewer lines of code
  • Easier to express some functions recursively than using iteration
• State a disadvantage of recursion

  • Inefficient use of memory
  • Danger of stack overflow
  • Difficult to trace
• Give two pieces of information that are stored on the call stack

  • Parameters
  • Return addresses
  • Local variables
• Define scope


  The section of the program in which a variable is accessible.
• Give two advantages of using local variables over global variables

  • Less memory is used
  • Self-contained so unaffected by code outside of the subroutine |
  • Take precedence over global variables with the same name
• What is top-down design?

  A technique used to modularise programs in which the problem is continually broken down into sub-problems, until each can be represented as an individual, self-contained module which performs a certain task.
• State two advantages of a modular design

  • Makes a problem easier to understand and approach
  • Simpler to divide tasks between a team
  • Easier to manage project
  • Self-contained modules simplify testing and maintenance
  • Greater reusability
• Give another name for top-down design

  Stepwise refinement
• What is the difference between procedures and functions?

  Functions must always return a single value while a procedure does not always have to return a value
• What does it mean to pass a parameter to a subroutine by reference?

  The address in memory of the parameter is passed to the subroutine so its value outside of the subroutine will be updated.
• State two features of IDEs.

  • Stepping
  • Variable watch
  • Breakpoint
  • Source code editor
  • Debugging tools
• What does IDE stand for?

  Integrated Development Environment
• What is encapsulation in object-oriented programming?

  When attributes are declared as private so can only be accessed and edited by public methods.
• Describe the purpose of encapsulation in object-oriented programming

  Program complexity is reduced by protecting data from being accidentally edited by other parts of the program.