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Part 8 - Drawing
=================
Many programmers want to draw in qbasic and there are many different ways, depending on what you
want to do!! Here is the code to draw a circle in screen 2 :
---------------------------------
screen 2
circle (x , y), radius, color
---------------------------------
The x and y stand for the coordinates you want the circle at, so you define these a number
eg 10, the radius is how big you want your circle, eg 10, and the color is used the same as
the color statement in part 6 so you also give that a number eg 3!!
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* Note : In screen 2 you cannot use colors!!!
---------------------------------------------
So an example of the code you could use would be :
----------------------------------------
cls
screen 2
circle (100,100),5,5
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This will draw a small circle, to draw a larger circle, you just increase the radius!!
To draw a line in screen 2, (obviously where x and y are your starting points, and y and y2 are
your finishing points) the code you need is:
--------------------------
line( x, y)-step( x2, y2)
--------------------------
We recommend screen 12 and 13, for drawing as they have the highest resolution.
============================
Part 9 - The Input Statement
============================
Input is a handy bit of qbasic code. What is it I hear you ask,well input means you can ask
the user a question and they can reply to it! Also as you learn more you can use the data
entered by the user for different things.
-------------------------
eg 1 - The Basic Question
-------------------------
The basic input statement is to ask a question to the user, to do this you use the following
code :
-------------------------------
CLS
INPUT "What is your name" ; q1$
-------------------------------
Please note you do not need a question mark because with input
'it automatically puts one in for you. Also the q1$ is there as qbasic stores the answer into
a variable called q1$ - there doesnt have to be a number just a letter or word, make sure its a
good word so you remember what its for, i chose q because it is for question, it could have been
called question$, or anything! Although it has to be a $.
------------------------
eg 2 - Using The Results
------------------------
To use the results of your question is easy, it just involves the print statement which you have
already learnt! I will show you two ways of displaying the answers to the question, D1 and D2:
D1 :
----------------------------------------
CLS
INPUT "What is your name" ; q1$
PRINT "Your name is " ;q1$
----------------------------------------
This stores the answer into the variable q1$ and then you are telling qbasic to type the answer
back out in the print statement. Please note to put a space after the "name" part in the input
statement or it will print; name and whatever the variable is as 1 word.
D2 :
----------------------------------------------------
CLS
INPUT "What is your name" ; q1$
CLS
PRINT "Your name is " ;q1$ ;" and i dont like you"
----------------------------------------------------
All i have done which is different to D1 is i have added a clear screen so the print statement
is on a blank screen, and looks better. Also I have added an extra bit at the end of the print
statement, this is just something I thought may be useful, it just means the name is put into
the middle of a sentence.
____________________
eg 3 - Using numbers
--------------------
There is a few good things qbasic can do with numbers in the input statment, however you have
to change the "$" to a "%" sign, so instead of being a variable it is stored as an integer
and qbasic knows that it is a number! This means if qbasic knows its a number you can do
some better things with it. Here is an example of how you tell qbasic you want the answer stored
as an integer :
--------------------------------------
CLS
INPUT "What is your age " ; age%
CLS
PRINT "So you are ";Age% ; " years old"
---------------------------------------
This puts the information into the integer age%, we can use this to perform simple sums :
------------------------------------------------------------------------------------------
CLS
INPUT "What is your age " ; age%
CLS
PRINT "So you are ";Age% ; " years old"
INPUT "What is your dads age " ; dadsage%
dadsage% - age% = differenceage%
CLS
PRINT "The difference in years between you and your dad is " ; differenceage%
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This has included a sum in to work out the difference in years between you and your dad,
it is just a simple minus sum! And from this it has produced a new integer called
differenceage%, as you know this could be called anything!
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This is the end of the StartingQB we hope it has helped be ready for part 2 and the other
tutorials that we will produce!
Keep checking Pickers Games Website, at www.pickersgames.co.uk
If you have any problems I can be emailed at:
pickers@pickersgames.co.uk
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thanks
Pickers
Pickers Games
www.pickersgames.co.uk
StartingQB was finished on 06/01/01
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