Page 1 of 15
Teachers guide to starting to
learn Just Basic
1 igover@somerset.gov.uk – April 2012
This guide is a suggestion in how to learn Just Basic1
. It is intended for educators and assumes
that Just Basic is already installed on the computer.
Most of this work is a summary of the tutorial to be found in the help menu. There is a lot of other
good help and guidance that can be found on the web.
Most the programs can be found here in a zipped file.
All good programmers plan what they are going to do before they complete a task. This ‘mission
statement’ is normally written in plain English as an algorithm (or pseudo code). Because of the
experiential nature of this tutorial this important step is highlighted in italics.
Program 1 – Working out VAT
In this first exercise we are going to create a program that:
1. Asks for an amount for goods before VAT is added;
2. Calculates a 20% VAT tax amount;
3. Displays the tax amount the total amount.
Type in the following into the main window
Click on will compile and run the program.
A new window should appear that allows you to enter an amount and then work out the VAT.
If you want to step through the program to see it working line by line click on . Move the
windows around so you see both the output window and the debugger.
Click on to step through the program line by line.
1
http://justbasic.com/
Page 2 of 15
Teachers guide to starting to
learn Just Basic
2 igover@somerset.gov.uk – April 2012
Program 2 – Checking the input for a zero amount
We are going to complicate our program by making it repeat every time and checking to see if the
amount entered is zero.
The algorithm becomes:
1. Asks for an amount for goods before VAT is added
2. Check to see if amount is greater than zero
a. If not display help file
3. Calculates a 20% VAT tax amount
4. Displays the tax amount the total amount
5. Returns to beginning of program
amount and tax are called variables.
Note the way in which label [start] and the sub routine help are used.
If you enter a number such as 123.12 into this program it will give you an answer of 147.744. Whereas this is true it
is not a good representation of money.
The INT() command can be used to round the number to 2 decimal places.
(int((tax*100)+0.5))/100 will round the VAT number to the correct number of decimal places
Page 3 of 15
Teachers guide to starting to
learn Just Basic
3 igover@somerset.gov.uk – April 2012
Program 3 – A number guessing game
This is a simple guessing game. The computer will pick a number between 1 and 100. The user
guesses the number in as few guesses as possible.
The algorithm is:
1. Pick a number between 1 and 100
2. Print program title and give some instructions
3. Ask for the user to guess number
4. Tally the guess
5. If the guess is right go to step (9)
6. If the guess is too low tell the user to guess higher
7. If the guess is too high tell the user to guess lower
8. Go back to step (3)
9. Beep and tell the user how many guess it took to win
10. Ask the user whether to play again
11. If the user answers yes then clear the guess tally and goto step (1)
12. Give the user instructions on how to close the game window
13. End the program
Compare the
program to the
algorithm.
The ‘grey
comments are
remark
statements
and can be
used if you
come back to
a program
after a long
while.