Computer Science
Structured English
Structured English is a way of describing an algorithm using a small subset of the English language and a few simple conventions.
There are no clear standards for Structured English.
Sequence
An instruction in Structured English should being with a verb.
For example,
INPUT hours worked
MULTIPLY hours worked by rate of pay
OUTPUT pay
When you have reached the section of the programming guides on procedures and functions, you will learn that it is common to group a series of statements like this into one logical block of code with a unique name in the program.
Imagine we had labelled the above algorithm with the unique name CalculatePay. We might then refer to this group of statements as follows,
DO CalculatePay
Assignment
In Structured English we use the term SET when we assign a value to a variable. For example,
SET hoursworked to 40
Selection
We have 3 main options to show selection in our algorithms,
- IF ... Then
- IF ... Then ... Else ...
- SELECT ...
For example,
IF error found
THEN OUTPUT "Error"
And,
IF error found
THEN OUTPUT "Error"
ELSE OUTPUT "All Fine"
And finally,
SELECT VALUE errorNumber
1: OUTPUT "Error Number 1"
3: OUTPUT "Error Number 3"
5: OUTPUT "That's a bad miss"
END SELECT
The indentation is good practice, makes the code easier to read and has to be seen as a compulsory part of the process.
Iteration
We can represent repetition in our algorithms using the following constructs in Structured English
FOR EACH employee
DO CalculatePay
And
REPEAT UNTIL no more employee records
READ next employee record
READ hours worked
READ pay rate
MULTIPLY pay rate by hours worked
And finally,
DO WHILE more employee records to process
READ next employee record
READ hours worked
READ pay rate
MULTIPLY pay rate by hours worked