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Repetitively clicking the mouse in the Stage area causes the Counter variable to count down in increments of oneand causes the counter variable to count down in increments of five.

Event-driven programming

The ability to write programs that cause certain operations to occur in response to events (such as pressing the space bar and clicking the mouse on the Stage) is often referred to as event-driven programming.

It is easy to write event-driven programs in Scratch. On the other hand, writing event-driven programs is not so easy in languages such asJava, C#, and C++. You need quite a lot of programming knowledge to write event-driven programs in those languages.

It is useful to give programming students a taste of event-driven programming early, if for no other reason than the factthat it tends to make programming more interesting.

Example blocks with pointed ends

The blocks shown in Image 4 are not used in this program. They are shown in this module to illustrate blocks with pointed endsreferred to earlier .

Image 4. example blocks with pointed ends.

Missing image.
Image 4. Example blocks with pointed ends.

Run the program

I encourage you to use the information provided above along with the Scratch 2.0 programming interface shown in Image 1 to write and run this program. Experiment with the code, making changes, and observing the results of yourchanges. Make certain that you can explain why your changes behave as they do.

A copy of this program has been posted online for your review.

I also encourage you to write the programs described below.

Student programming projects

The following projects are designed to:

  • Help the student retain the knowledge gained by studying the module.
  • Require the student to think beyond the material presented in the module by requiring the student to answer the question "How do I ...?"

Project 1

Begin with the program named Variable01 and modify it to create a new program named Variable02 . Modify the original program in such a way that pressing the space bar five times in succession, (after clicking the green flag to set both variables to zero) , will cause the displayed values of the variables named Counter and counter to be as shown in Image 5 .

Image 5. output from project 1.

Missing image.
Image 5. Output from Project 1.

Having reached that point, clicking the mouse five times in succession in the Stage area will cause the displayed values of the variables named Counter and counter to be as shown in Image 6 .

Image 6. output from project 1.

missing image
Image 6. Output from Project 1.

A copy of this program is posted online for your review.

Project 2

You should successfully complete Project 1 before attempting this project. Begin with the program named Variable01 and modify it to create a new program named Variable03 . Modify the original program in such a way that pressing the space bar five timesin succession, (after clicking the green flag to set both variables to zero) , will cause the displayed values of the variables named Counter and counter to be as shown in Image 7 .

Image 7. output from project 2.

Missing image.
Image 7. Output from Project 2.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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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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