COMPUTER SCIENCE YEAR 8
SUBJECT: COMPUTER SCIENCE
TERM: SUMMER
CLASS: YEAR 8
SCHOOL: SQUARE COLLEGE
SESSION: 2023/2024
TEACHER: MRS MARK
ALGORITHM AND DATA 1 & 2
ALGORITHM, PSEUDOCODE, FLOWCHART
Mrs Mark
What is an algorithm?
An algorithm is a plan, a set of step-by-step instructions to solve a
problem. In an algorithm, each instruction is identified and the order in
which they should be carried out is planned. Algorithms are often
used as a starting point for creating a computer program
Representing an algorithm: Pseudocode
There are two main ways that algorithms can be represented –
pseudocode and flowcharts.
Most programs are developed using programming languages.
These languages have specific syntax that must be used so that the
program will run properly. Pseudocode is not a programming
language, it is a simple way of describing a set of instructions that
does not have to use specific syntax. Mrs. Mark
Writing in pseudocode is similar to writing in a programming language.
Each step of the algorithm is written on a line of its own in sequence.
Usually, instructions are written in uppercase, variables in lowercase
and messages in sentence case. In pseudocode, INPUT asks a
question. OUTPUT prints a message on screen.
A simple program could be created
to ask someone their name and age, OUTPUT 'What is your name?'
and to make a comment based on INPUT user inputs their name
STORE the user's input in the name variable
these. This program represented in OUTPUT 'Hello' + name
pseudocode would look like this: OUTPUT 'How old are you?'
INPUT user inputs their age
STORE the user's input in the age variable
IF age >= 70 THEN
OUTPUT 'You are aged to perfection!'
ELSE
Mrs. Mark OUTPUT 'You are a spring chicken!'
Representing an algorithm: Flowcharts
A flowchart is a diagram that represents a set of instructions. It can be defined
as pictorial representation of an algorithm. Flowchart symbols
Mrs Mark
PRINT PRINT
“PASS” “FAIL”
Mrs Mark
PRINT
Lcm
Mrs Mark
PRINT
A
Mrs Mark
Print x1, x2
Mrs Mark
PRINT PRINT
A B
Mrs Mark
PRINT PRINT
A B
Mrs Mark
>=
<=
<>
Mrs Mark
Print
“The largest value is”,
MAX
Mrs. Mark
