2.2.1 Programming Techniques

Question 1

Sequence

Answer 1

Code is executed line-by-line, from top to bottom

Question 2

Selection

Answer 2

A certain block of code is run if a specific condition is met, using IF
statements. This is also known as ‘branching’.

Question 3

Iteration

Answer 3

Can be either:

Count-controlled

• Block of code executed a certain number of times

Condition-controlled

• Block of code is executed while a condition is met

Uses FOR, WHILE or REPEAT UNTIL loops

Question 4

Recursion

Answer 4

• Programming construct in which a subroutine calls itself during its execution
• Continues until a stopping condition is met
• produces the same result as iteration, but is more suited to certain problems

Question 5

Recursion - Advantages

Answer 5

• Can be represented in fewer lines of code (for some problems), making them less prone to errors
• Easier to express some functions recursively eg. Factorial

Question 6

Recursion - Disadvantages

Answer 6

• Inefficient use of memory
• Risk of stack overflow if memory runs out
• Difficult to trace (especially with more and more function calls)

Question 7

Variables

Answer 7

• Variables can be defined with either global or local scope
• Scope is the section of code in which the variable can be accessed
• A local variable within a subroutine takes precedence over a global variable with the same name

Question 8

Local Variables

Answer 8

• Can only be accessed within the subroutine in which they were defined
• Multiple local variables with the same name can exist in different subroutines
• Are deleted once subroutine ends
• Using local variables ensures subroutines are self-contained - good
  programming practice

Question 9

Global Variables

Answer 9

• Can be accessed across the whole program
• Useful for values that need to be used by multiple parts of the program
• Danger of being unintentionally edited and overwritten
• Not deleted until program terminates, so require more memory

Question 10

Modular Programming

Answer 10

• A programming technique used to split large, complex programs into smaller, self-contained modules.
• Modularity is essential to making a problem easier to understand and approach.

Question 11

Benefits of a Modular Approach

Answer 11

• Easier to divide tasks between a team and manage projects
• Simplifies the process of testing and maintenance, as each component can be dealt with individually
• Improves reusability of components - once a module has been tested, it can be reused with confidence

Question 12

Top-Down Approach

Answer 12

• Technique used to modularise programs
• Problem is broken down into sub-problems, until each is represented as an individual, self-contained module which performs a certain task
• Modules form blocks of code called subroutines

Question 13

Functions vs Procedures

Answer 13

• Both named blocks of code that perform a specific task
• Procedures do not return a value
• Functions must always return a single value (some languages, like Python, allow functions to return multiple values using tuples)
• Parameters can be passed into a subroutine either by value or by reference

Question 14

Passing By Value

Answer 14

• A copy of the value is passed to the subroutine and discarded at the end
• Its value outside of the subroutine remains unaffected

Question 15

Passing By Reference

Answer 15

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

Question 16

IDE

Answer 16

Program which provides a set of tools to make it easier for programmers to
write, develop and debug code

Question 17

Benefits of Using an IDE to Write Code

Answer 17

• Source Code Editor
• Autocorrect
• Autocompletion
• Pretty Printing
• Syntax Highlighting
• Auto-documentation
• Code Editors
• Translators

Question 18

Source Code Editor

Benefits of Using an IDE to Write Code

Answer 18

The editor aims to make the coding process easier by providing features such as autocompletion of words, indentation, syntax highlighting, and automatic bracket completion.

Question 19

Autocorrect

Benefits of Using an IDE to Write Code

Answer 19

Automatically corrects typos and common syntax errors as you type, enhancing productivity and reducing the number of minor errors.

Question 20

Autocompletion

Benefits of Using an IDE to Write Code

Answer 20

Provides suggestions for code completion based on the context, which helps speed up coding by reducing the amount of typing and preventing syntax errors.

Question 21

Pretty Printing

Benefits of Using an IDE to Write Code

Answer 21

Automatically formats the code to be more readable with proper indentation and line breaks, making it easier to understand and maintain.

Question 22

Syntax Highlighting

Benefits of Using an IDE to Write Code

Answer 22

Uses different colors and fonts to distinguish various elements of the code (e.g., keywords, variables, strings), improving readability and helping to quickly identify errors.

Question 23

Auto-documentation

Benefits of Using an IDE to Write Code

Answer 23

Generates documentation automatically based on the code and comments, which helps keep the documentation in sync with the code and improves understanding for other developers.

Question 24

Code Editors

Benefits of Using an IDE to Write Code

Answer 24

Provide an environment for writing and editing code with features that enhance productivity, such as syntax highlighting and autocompletion.

Question 25

Translators

Benefits of Using an IDE to Write Code

Answer 25

Components like compilers or interpreters that translate the written code into machine code or bytecode that can be executed by a computer.

Question 26

Benefits of Using an IDE to Test Code

Answer 26

• Breakpoints
• Stepping
• Variable Watch Window
• Debugging Tools
• Error Diagnostics
• Runtime Environments

Question 27

Breakpoints

Answer 27

IDEs allow users to set a point in the program at which the program will stop. This can either be based on a condition or set to occur at a specific line. This can help to pinpoint where an error is occurring.

Question 28

Stepping

Answer 28

This allows you to monitor the effect of each individual line of code by executing a single line at a time. It’s useful for debugging and understanding the program flow.

Question 29

Variable Watch Window

Answer 29

Sometimes used to pinpoint errors, this is a useful feature to observe how the contents of a variable change in real-time through the execution of a program.

Question 30

Debugging Tools

Answer 30

Some IDEs also provide run-time detection of errors with a guide as to where in the code they are likely to have occurred through line numbers and highlighting.

Question 31

Error Diagnostics

Answer 31

Tools that help identify and diagnose errors in the code, providing detailed information about what went wrong and where.

Question 32

Runtime Environments

Answer 32

Environments within the IDE that allow code to be run and tested directly, often with integrated debugging tools to monitor the execution.

Question 33

Use of Object Orientated Techniques

Answer 33

• Object-oriented languages are built around the idea of classes
• A class is a template for an object
• Classes define the state and behaviour of an object
• Object state is given by attributes while behaviour is defined by methods
• An object is a particular instance of a class
• Attributes cannot be directly edited in a technique called encapsulation
• Top-down design applies encapsulation to modules, which are also built to be self-contained and reusable