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Functions

Variables

Variables 2

Inputs

Selection

Flowcharts

​Data types

Pseudocode1

Pseudocode2

Subprogram1

Subprogram2

Pseudocode (pronounced "Sue-doe-code")

Psedocode looks a lot like a programming language but it isn't, because computers don't understand it. It is because Humans understand pseudocode and computers do not, that makes pseudocode really useful. Professional programmers that make software, apps or playstation games normally know how to write code in just one of the hundreds of different programming languages. This means that if you have a team of programmers that all understand different programming languages and you want them all to make a new game, you can write the code in pseudocode and give them each a copy. They will be able to understand your pseudocode and then write code in the programming language they understand.
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  • Think of pseudocode as being a text version of a flowchart. Computers wont understand a flowchart but programmers will. Programmers will be able to use a flowchart to write code.

  • Definiton of pseudocode: Written instructions that looks like code, but is understood by human programmers and not computers.

Pseudocode explained

How much pseudocode is there?

Below is a list of pseudocode constructs that have already been covered. Click here for a PDF version.

Variables

Pseudocode syntax
Explanation of syntax
Example(s)
Python code example
SET Variable TO <value>
Assigns a value to a variable. 
​SET Counter TO 0
SET MyString TO ‘Hello’
Counter = 0
MyString = "Hello"
SET Variable TO <expression>
Computes the value of an expression and assigns to a variable.
​SET Sum TO Score + 10
SET Size to LENGTH(Word)
Sum = Score + 10
Size = len(word)

Selection

Pseudocode syntax
Explanation of syntax
Example(s)
Python code example
 IF <expression> THEN
  <command>
​END IF
If <expression> is true then command is executed.
IF Answer = 10 THEN 
   SET Score TO Score + 1
END IF
​if Answer == 10:
  Score = Score + 10
​IF <expression> THEN
  <command>
ELSE
  <command>
END IF
​If <expression> is true then first <command> is executed, otherwise second <command> is executed.
IF Answer =‘correct’ THEN
  SEND ‘Well done’ TO DISPLAY
ELSE
  SEND ‘Try again’ TO DISPLAY
END IF
if Answer == "correct":
  print("well done")
else:
  print("Try again")

Input/Output

Pseudocode syntax
Explanation of syntax
Example(s)
Python code example
SEND <expression> TO DISPLAY
Sends output to the screen.
SEND ‘Have a good day.’TO DISPLAY
print("have a good day")
RECEIVE <identifier> FROM (type) <device>
Reads input of specified type.
​RECEIVE Name FROM (STRING) KEYBOARD
Name=input("Enter name")

Subprograms

Pseudocode syntax
Explanation of syntax
Example(s)
Python code example
PROCEDURE <id> (<parameter>)
BEGIN PROCEDURE
  <command>
END PROCEDURE
Defines a procedure.
PROCEDURE CalculateAverage (Mark1, Mark2, Mark3)
BEGIN PROCEDURE
   SET Avg to (Mark1 + Mark2 + Mark3)/3
END PROCEDURE
​def CalculateAverage(Mark1, Mark2, Mark3):
   Avg=(Mark1 + Mark2 + Mark3)/3
FUNCTION <id> (<parameter>)
BEGIN FUNCTION
   <command>
RETURN <expression>
END FUNCTION
Defines a function.
​FUNCTION AddMarks (Mark1, Mark2, Mark3)
BEGIN FUNCTION
   SET Total to (Mark1 + Mark2 + Mark3)/3
RETURN Total END FUNCTION
​def AddMarks (Mark1, Mark2, Mark3)
 Total = (Mark1 + Mark2 + Mark3)/3
 return Total

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