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Image 3. programming blocks in the events category.

Missing image.
Image 3. Programming blocks in the Events category.

The finished program

The rightmost panel in Image 1 shows the finished program. I created the program by dragging blocks fromthe Data toolbox and the Events toolbox and snapping them together to form three separatescripts.

(Actually the program that you see in Image 1 is the result of an automatic conversion from v1.4 to v2.0 that was performed by the folks at MIT during the transition period fromv1.4 to v2.0. I originally wrote that program in v1.4. Some of the toolboxes had different names in v1.4.)

Note that I also entered literal values of 0, 1, 5, -1, and -5 into the white text fields in the programming blocks for the variables after dragging them intothe programming area.

In addition, I used the pull-down list on each of six orange Data blocks in Image 1 to select the name of the variable to which that block applies. (Note that each of those six blocks refers either to Counter or counter .)

Behavior of the program

Click the green flag

The program contains three scripts. Each script remains silent until a specific event occurs. As the label on the uppermostblock in the top programming script in Image 1 indicates, the code in the top script in Image 1 is executed once each time the user clicks the green flag shown in the upper right ofthe stage. This code causes the values stored in each of the two variables to be set to zero. This, in turn causes thevariable displays in the Stage area to each show a value of 0.

Press the space bar

Because of the top block in the middle script reads "when space key pressed" , the code in the middle script is executed once each time the user presses the space bar.

The pull-down list on this block allows you to select among the keys on the keyboard with the space bar being the default.

One of the orange programming blocks in the middle script causes the value of the variable named Counter to change by +1 when the space bar is pressed. The other orangeprogramming block causes the value of the variable named counter to change by +5 when the space bar is pressed.

In other words, repetitively pressing the space bar causes the Counter variable to count up in increments of one and causes the counter variable to count up in increments of five.

Click the mouse on the Stage

Because of the top block in the bottom script reads "when this spriteclicked" , the code in the bottom script in Image 1 is executed once each time the user clicks the mouse in the large white Stagearea shown in Image 1 .

(In this case, there are no sprites so this event is triggered by clicking the stage. I believe this isa new label on this block in v2.0. This label, which refers to a sprite, seems to be a little too specific.)

The bottom two blocks in this script are the same as the bottom two blocks in the middle script except that the algebraic signs on the two literal values are minus instead of plus.

The absence of a "-" character causes a literal value to be positive. A "+" character is notrequired for positive literal values.

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Teaching beginners to code. OpenStax CNX. May 27, 2013 Download for free at http://cnx.org/content/col11498/1.20
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