Flowchart and Pseudocode

Flowcharts

To be able to create a meaningful flowchart, an algorithm must first be created. Algorithm can be developed into Pseudocode. This takes each step and revises them into a from called structured.

The Step-by-step instructions used to solve a problem can be used to create a diagram which is called Flowchart. It uses symbol to represent the different types of instructions. The flowchart symblos are linked togheter with arrows showing the direction of flow.

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Pseudocode

The algorithm can then be taken and be changed into pseudocode. This is fake programming language.

It does not hvae any computing commands. It helps you to think through the problem and ensure that the solution work.

Before pseudocode can be written some basic programming concepts need to be understood.

Command	Description
Variable	storage mechanism where the data can change be updated for example results of calculation
Constants	storage mechanism where data that does not change through the running of a program
Key processes	if statements, calculations
Repeated process	loops used to repeat specific parts of a program
Inputs	these are inputs into the program, this can be from the keyboard or mouse, etc...
Outputs	these are outputs to the screen

Pseudocode must be laid out in a particular way. The code must be indented. This means that it must be tabbed across the page.

Think of indentation as a replacement for brackets like in math's. It means one set code is related to the outer set.

Example 1

BEGIN
    SET age
    INPUT age
    IF age is greater than 17
        DISPLAY you can vote.
    ELSE
        DISPLAY you cannot vote.
        SET vote
        END IF
END

Example 2

{
SET age​
INPUT age​
IF age is greater than 17​
DISPLAY you can vote.​
ELSE​
DISPLAY you cannot vote.​
SET Vote​
}

Which is easier to read?

• Example-1
• Example-2

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How to Write Pseudocode

Command	Execute	Description
Start/End	BEGIN and END	Used to show the start of the program and the end of the program
Input	INPUT, READ or OBTAIN	This is anything entered into the program
Outputs	PRINT or DISPLAY	This is to display something to the user or send something to the printer​
Processes	CALCULATE, SUM or GENERATE	This is carries out an action or task
Variables	SET or INITIALISE	Initialise a variable to be used to store data or update the data
Loop/Iteration	WHILE REPEAT - UNTIL	a loop (iteration that has a condition at the beginning)​ a loop (iteration) that has a condition at the end​
Decision/Conditional	IF - THEN - ELSE	a decision (selection) in which a choice is made​ any instructions that occur inside a selection or iteration are usually indented​

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Repeats

Repeat is a command that create a repetiontion for a spcific block of code. This is called "for loop"

{
REPEAT
    DISPLAY Insert card
    INPUT card details
    SET card details
    IF card is invalid
        card not accepted
    ELSE
        card is accepted
UNTIL card is accepted
SET oddNumbers to 0
FOR count = 1 to 10
    DISPLAY count 
    SET count + 2
END FOR
}

IF

These use a condition to make a decision

{
IF card is invalid
        card not accepted
    ELSE
    card is accepted
}