Programming Techniques Flashcards
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.
