Paper 2

Last minute exam notes to go through before sitting the Paper 2 exam.

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Local Variables

• Only accessible within a function

• Not visible outside the function

• Used to store temporary data or values

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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

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Types of Test Data

There are 4 types (for more info go here):

1. Normal

2. Abnormal

3. Extreme

4. Boundary

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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.

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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.

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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.

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Types of Statements

1. Conditional Statements Used to make decisions in a program (e.g. an if / case statement)

2. Iteration (or looping) Statements Repeats a block of code multiple times (e.g. a for / while loop)

3. Assignment Statements Where you are assigning a value to a variable (e.g. x = 5)

4. Input / Output Statements

5. Declaration Statements You declare the data type of a constant or variable (e.g. string, integer)

6. Contol Transfer Statements This is when you change the flow of a program (e.g. using break / return)

7. Function Call Statements

8. Exception Handling Statements To deal with error handling (e.g. using try / catch)

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SQL Commands

Look through this list and understand what each one does. Revise here.

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Types of Checks

This comes up frequently in exam questions. Read up on it here.

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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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