Flowcharts (SQA National 5 Computing Science): Revision Note

Flowcharts

What is a flowchart?

• A flowchart is a design technique that shows the steps needed to solve a problem

• It uses standard symbols to represent the flow of data and control through a program

• Flowcharts show inputs, processes, decisions, loops, and outputs

• They are read from top to bottom and left to right

• Lines or arrows show the order of execution

Flowchart symbols

Symbol	Name	Description
	Terminal	Shows the start or end of an algorithm
	Initialisation	Used to show a variable being declared or given a starting value
	Input/Output	Represents data being entered or displayed
	Decision	Represents a question or condition with Yes/No branches
	Process	Shows a calculation or instruction that changes data
	Pre-defined function	Represents a subprogram, function, or procedure that has already been defined elsewhere
	On-page connector	Used when a flowchart continues elsewhere on the same page
	Flow line	Show the order in which steps are carried out

Example

• A gambling website wants to check a members age to inform them if they are ok to enter

• An example flowchart is

• They would like the algorithm refined so that the user also enters their first name and this is used to greet the user when they access the site

• A new input box was added, along with updating the output box to include the variable fname collected from the user