2.2.1 Programming Techniques

Question 1

Name 3 programming constructs.

Answer 1

Sequence
Selection
Iteration

Question 2

What is meant by sequence?

Answer 2

Code is executed line-by line from top to bottom

Question 3

What is meant by selection?

Answer 3

Particular block of code is run if a specific condition is met

Question 4

Which statements are examples of selection?

Answer 4

If
Else

Question 5

Name the 2 types of iteration.

Answer 5

Count-controlled
Condition-controlled

Question 6

What is meant by count-controlled iteration?

Answer 6

Block of code executed a certain number of times

Question 7

What is meant by condition-controlled iteration?

Answer 7

Block of code executed while a condition is met

Question 8

Which loops are examples of iteration?

Answer 8

For
While

Question 9

What is recursion?

Answer 9

A programming construct in which a subroutine calls itself during its execution

Question 10

How long does recursion continue?

Answer 10

Until a stopping condition is met

Question 11

Give 2 advantages of recursion.

Answer 11

Can be represented in fewer lines of code
Easier to express some functions recursively

Question 12

Give 2 disadvantages of recursion.

Answer 12

Risk of stack overflow if memory runs out
Difficult to trace

Question 13

Which two ways can variables be defined?

Answer 13

Within a global scope
Within a local scope

Question 14

What is meant by scope?

Answer 14

The section of code in which a variable can be accessed

Question 15

Where can local variables be accessed?

Answer 15

Only within the subroutine in which they are defined

Question 16

Where can global variables be accessed?

Answer 16

Across the whole program

Question 17

What are 2 benefits of local variables?

Answer 17

Ensures subroutines are self-contained
Multiple local variables with the same name can exist in different subroutines

Question 18

What are 2 disadvantages of global variables?

Answer 18

Requires more memory as not deleted until program terminates, local variables are deleted once the subroutine ends
Danger of being unintentionally edited

Question 19

What is modular programming?

Answer 19

A technique used to split large, complex programs into smaller, self-contained modules

Question 20

Give 3 benefits of using modular programming.

Answer 20

Improves reusability of components
Simplifies testing & maintenance
Easier project management

Question 21

What is stepwise refinement / top-down design?

Answer 21

Technique used to modularise programs by breaking down problem into sub-problems until each is an individual, self-contained module performing a certain task

Question 22

What is a function?

Answer 22

Named block of code that performs a specific task
Always returns a single value

Question 23

What is a procedure?

Answer 23

Named block of code that performs a specific task
Do not have to return value

Question 24

State the two methods by which parameters can be passed.

Answer 24

By reference
By value

Question 25

What is meant by passing by value?

Answer 25

A copy of the value is passed to the subroutine and discarded at the end
Value external to subroutine remains the same

Question 26

What is meant by passing by reference?

Answer 26

Address of parameter is given to subroutine
Value will be updated at given address

Question 27

What does IDE stand for?

Answer 27

Integrated Development Environment

Question 28

What is an IDE?

Answer 28

Program providing a set of tools that allow programmers to write, develop & debug code easily

Question 29

State the 5 common features of IDEs.

Answer 29

Stepping
Variable watch
Breakpoint
Source code editor
Debugging tools

Question 30

What is meant by stepping?

Answer 30

Executes a single line at a time
Allows programmer to monitor the effect of each individual line of code

Question 31

What is meant by variable watch?

Answer 31

Used to observe how the contents of a variable change in real-time through the execution of a program

Question 32

What is meant by breakpoint?

Answer 32

Allows programmer to set a point in the program for it to stop
Either based on a condition or at specific line
Helps pinpoint errors

Question 33

What is meant by source code editor?

Answer 33

Aims to make coding process easier
Includes autocompletion of words, indentation, syntax highlighting & automatic bracket completion

Question 34

What is meant by debugging tools?

Answer 34

Run-time detection of errors with a guide to where in the code they are likely to have occured through line numbers and highlighting

Question 35

What is a class?

Answer 35

A template for an object
Defines the state & behaviour

Question 36

How is the state of an object defined?

Answer 36

Attributes
Give an object’s properties

Question 37

How is the behaviour of an object defined?

Answer 37

Methods
Describe actions an object can perform

Question 38

What is instantiation?

Answer 38

An object is an instance of a class
A class can be used to create multiple objects with the same set of attributes & methods

Question 39

What is encapsulation?

Answer 39

Attributes are declared as private so can only be altered by public methods

Question 40

Why is encapsulation used?

Answer 40

Makes programs less complex by protecting data from being accidentally edited