2.2.1 Programming techniques

Question 1

What is sequencing?

Answer 1

• Code is executed line-by-line top to bottom

Question 2

What is branching?

Answer 2

• Section of code is only run if specifc condition met

Question 3

What is iteration?

Answer 3

• Block of code executed more than once
• Count-controlled: certain number of times
• Condition-controlled: while condition is met

Question 4

What is recursion?

Answer 4

• Programming construct where sub-routine calls itself
• Continues until base case is met

Question 5

Advantages of recursion?

Answer 5

• Code can be represented in fewer lines
• Easier to express some functions recursively

Question 6

Disadvantages of recursion?

Answer 6

• Risk of stack overflow if memory runs out
• Difficult to trace

Question 7

Variable facts

Answer 7

• Defined with either global or local scope
• Scope is section of code which variable can be accessed
• Local variable with same name is subroutine overwrite global variable

Question 8

What is a local variable?

Answer 8

• Defined within subroutine
• Can only be accessed within subroutine
• Are deleted when subroutine ends
• Ensures subroutines are self contained

Question 9

What is a global variable?

Answer 9

• Can be accessed across entire program
• Useful for values which are accessed often
• Risk being unintentionally edited
• Not deleted therefore more memory

Question 10

What is modularity?

Answer 10

• Splitting large programs into smalled self-contained modules
• Easier to divide tasks between team
• Each component can be tested individually

Question 11

What are functions and procedures?

Answer 11

• Sections of code that perform specific task
• Procedures dont return value
• Functions return single value

Question 12

What is passing by value?

Answer 12

• Copy of value is passed to subroutine
• Creates local copy
• Value outside subroutine is unaffected

Question 13

What is passing by reference?

Answer 13

• Address of parameter passed into subroutine
• Value of parameter updated at given address

Question 14

What are IDEs?

Answer 14

• Program that provides set of tools to help programmers develop and debug code

Question 15

Features of IDEs?

Answer 15

• TREE: translators, run time env, error diagnostics, editing
• CASA: Colour coding, automatic indentation, stepping, autocomplete

Question 16

What is a class?

Answer 16

• Template used to create objects
• Contains attributes defining object state
• Contains methods defining object behaviour

Question 17

What is encapsulation?

Answer 17

• Attributes cannot be directly edited or accessed

Question 18

What is inheritence?

Answer 18

• Child class inherits methods and attributes of parent class

Question 19

What is polymorphism?

Answer 19

• Inherited methods produce different outputs to that of parent class