Pseudo Code

How to write pseudocode

There are six basic computer operations

1. A computer can receive information

Read (information from a file)

Get (information from the keyboard)

2. A computer can put out information

Write (information to a file)

Display (information to the screen)

3. A computer can perform arithmetic

Use actual mathematical symbols or the words for the symbols

Add number to total

Total = total + number

+, -, *, /

Calculate, Compute also used

4. A computer can assign a value to a piece of data

3 cases

to give data an initial value

Initialize, Set

To assign a value as a result of some processing

‘=’

* x = 5 + y

to keep a piece of information for later use

Save, Store

5. A computer can compare two piece of information and select one of two alternative actions

IF condition THEN

some action

ELSE

alternative action

ENDIF

6. A computer can repeat a group of actions

WHILE condition (is true)

some action

ENDWHILE

FOR a number of times

some action

ENDFOR

The Structure Theorem (and the pseudocode we use to represent the control structures)

It is possible to write any computer program by using only three basic control structures: sequence, selection, repetition.

Sequence

Execution of one step after another. This is represented as a sequence of pseudocode statements:

Statement 1

Statement 2

Statement 3

Example:

Read three numbers

Add three numbers

Display total of three numbers

Selection...