1. Pseudocode
Key Revision Points

2. NOTE
The basic syntax you’ll need in your exam is provided in this presentation
Practice writing pseudocode is just as (more!!!) important than knowing the syntax
Use the past paper practice questions provided to develop your skills!

3. PSEUDOCODE Used by programmers to write algorithms/ plan programs
Not a real programming language (although it contains “program like” syntax)
Can be translated into any programming language

4. INPUT/OUTPUT
Equivalent to input and print in Python. Don’t forget input always needs to be assigned somewhere i.e. a variable
OUTPUT “Hello Bert”
OUTPUT “Which way do you want to go?”
direction  USER INPUT
Distance  INT(USER INPUT)

5. ASSIGNMENT
Use an arrow to indicate assignment. Equivalent to using a single = sign in Python
Arrow always points to the left!
Indicating the variable type is optional but if in doubt do it!
INT x  42
STRING user  “Bert”
CHAR initial  ‘A’
BOOL gameOver  TRUE
STRING choice  USER INPUT
INT choice  INT(USER INPUT)

6. CONDITIONALS Equivalent to if/elif/else in Python Must have an END IF
Example:
IF name = “Bert” THEN
OUTPUT “Hello Bert”
ELSE IF name = “Fred” THEN
OUTPUT “Hello Fred”
ELSE
OUTPUT “Who are you?”
END IF
Note the single = sign in if/elif part. It’s the comparison operator NOT the assignment operator. Equivalent to == in Python

7. NESTED CONDITIONALS
Must have two (or more) END IF statements – one for each IF
Example:
IF age < 18 THEN
OUTPUT “Discount”
ELSE
IF age > 65 THEN
OUTPUT “Full price”
END IF

8. ITERATION - FOR Python – for i in range(0,10):
Pseudocode – FOR i  0 TO 9 DO
Code inside the for block should be indented
Don’t forget END FOR
For nested loops you need multiple END FORs

9. ITERATION - WHILE Python: while x<=100:
Pseudocode: WHILE x <= 100 DO
Code inside the for block should be indented
Don’t forget END WHILE
For nested loops you need multiple END WHILEs

10. ARRAYS
Indexing can start at 0 or 1. AQA often uses 1. Examples below make this assumption
Declare and initialise an array
INT myArray  [5,3,2,7]
Reassign values in an array
myArray[2]  6
myArray[3]myArray[3]+4
Access values in an array
OUTPUT myArray[1]
myNum  myArray[2]

11. 2D ARRAYS
Indexing can start at 0 or 1. AQA often uses 1. Examples below make this assumption
Each element has a “row” and “column” index
Declare and initialise a 2D array
INT my2DArray  [[5,3],[2,7],[4,1]]
Reassign values in an array
my2DArray[2][1]  6
my2DArray[3][2]my2DArray[3][2]+4
Access values in an array
OUTPUT my2DArray[1][2]
myNum  my2DArray[2][2]

12. ARRAY NOTE
There is no pseudocode for appending to (or deleting from) an array
By definition an array’s size is fixed at declaration – you can’t add more elements

13. FUNCTIONS Must have at least one RETURN Don’t forget END FUNCTION
Include the parameters and type
Code inside function should be indented
FUNCTION getArea(INT width, INT height)
INT area  width * height
RETURN area
END FUNCTION

14. PROCDEURES Does NOT have a RETURN Don’t forget END PROCEDURE
Include the parameters and type
Code inside procedure should be indented
Can use PROC instead of procedure
PROCEDURE showArea (INT area)
OUTPUT “The area is “ + STR(area)
END PROCEDURE