Paper 2
Last minute exam notes to go through before sitting the Paper 2 exam.
Local Variables
Only accessible within a function
Not visible outside the function
Used to store temporary data or values
Global Variables
Accessible throughout the whole program and visible throughout the code
Variable exists as long as the program is running
Used to store values that need to be modified or accessed by the program
Types of Test Data
There are 4 types (for more info go here):
Normal
Abnormal
Extreme
Boundary
Data Types
You can have a string, character, Boolean, integer, and a real number.
To define a string -> it's a group of characters consisting of letters, numbers, and special characters. To define a character -> it's a single character, or letter
If asked to give an example of any of the above, make sure that your answer includes everything within the definition of that specific data type.
Example: if asked to give an example of a string. You must say (Variable2024!) to show that the string can include all of those characters. While if asked about a boolean, you can say either true or false.
In Python a real value, is equivalent to a float value.
Functions
The main thing to note is the difference between defining and calling a function.
When you are defining a function, you are creating that function. It's where you specify what the functions should do.
When you are calling a function, you are using the function you defined and you are telling the program to execute the code inside that function.
Flowchart Symbols
Will most likely come up. Need to know the symbols mean and be able to explain what they do. All info about flowcharts can be found here.
Types of Statements
Conditional Statements Used to make decisions in a program (e.g. an if / case statement)
Iteration (or looping) Statements Repeats a block of code multiple times (e.g. a for / while loop)
Assignment Statements Where you are assigning a value to a variable (e.g. x = 5)
Input / Output Statements
Declaration Statements You declare the data type of a constant or variable (e.g. string, integer)
Contol Transfer Statements This is when you change the flow of a program (e.g. using break / return)
Function Call Statements
Exception Handling Statements To deal with error handling (e.g. using try / catch)
SQL Commands
Look through this list and understand what each one does. Revise here.
Types of Checks
This comes up frequently in exam questions. Read up on it here.
Definitions
Pre-Condition Loop Condition is evaluated before the loop is executed (e.g. a while loop).
Post-Condition Loop Condition is evaluated afterwards so the loop executes regardless of the condition (e.g. a repeat until loop).
Constant A value that is set once and cannot be changed during the execution of the program. Is used instead of a variable if the variable shouldn't change during the program's execution.
Variable A storage location in memory with a name that is used to hold data that can change during the program's execution.
Array A data structure that holds multiple values of the same data type indexed by position.
Library Routines A collection of standard programs available for immediate use.
Subroutine Performs a specific task and does not necessarily return a value (generally used to execute a set of instructions that are used frequently). It can be called when required and used by other programs.
Abstraction When you simplify a problem by removing unnecessary details from the problem and filtering out irrelevant characteristics from elements.
Function Performs a specific task and returns a value when called (generally used to perform calculations which are used later on in the code).
Primary Key The field that is used has to be a unique identifier or alphanumeric value.
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