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Can also use a variable

Note that I also created a dummy variable in Image E for illustration purposes. Because the shape of a variable block is the same as the shape of thewhite box in the repeat block, you can also drop a variable block into the box. When you do this, the value of the variable will be used to determinehow many times the code in the block will be executed. That number may be different each time the repeat block is executed.

The wait block

Image E also shows a wait block, which can be dragged into the center panel from the Control toolbox. Like the repeat block, the wait block has a white box into which you can either enter a literal value or drop a variable block.

The program will pause for a specified number of seconds (which may be a decimal fraction) each time the wait block is executed. If you enter a literal value into the box, the program will pause for the same amountof time each time the wait block is executed. If you drop a variable block into the box, the length of the pause will be the current value stored inthe variable, which may be different each time the block is executed.

The switch costume block

Finally, Image E shows a purple switch to costume block. This block is available in the purple Looks toolbox when a sprite icon is selected immediately below the stage. However, when the Stage icon is selected, theblock changes to one labeled switch to backdrop . (A discussion of backdrops will be deferred to a future module.)

As you can see, the switch to costume block has a pull-down list that allows you to select a specific costume for the block when you write theprogram. The list contains all of the costumes belonging to the selected sprite. In the case of the default cat that appears for new projects, there are two costumes in the pull-down listbecause the cat has two costumes as shown in Image D .

The program code

The code for this program is shown in Image F .

Image f. program code for the program named forloop01.

Missing image.
Image F. Program code for the program named ForLoop01.

Behavior of the program

When the user clicks the green flag, the cat moves to the center of the stage (the origin of the Cartesian coordinate system) and turns to face the viewer's right. In addition, the cat switches to costume1 (see Image D ) even if that isn't necessary at this point. (Except for switching costumes, you have seen code like this in earlier modules.)

The repeat block

Then the code inside the repeat block shown in Image F is executed 24 times in succession.

During each execution (iteration) of the repeat block, the cat:

  • Moves 10 steps forward.
  • Waits 0.1 second.
  • Switches to costume2.
  • Rotates around its own origin by 15 degrees.
  • Waits an additional 0.1 seconds.
  • Switches back to costume 1.

This causes the cat to appear to walk (in a rather jerky fashion) in a circle (see Image G ) , ending up very close to where it started.

Image g. the cat on the stage.

Missing image.
Image G. The cat on the Stage.

Run the online version

In order to get the full impact of this program, you will either need to create the program yourself or run the online version (see Resources ) .

Questions & Answers

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
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
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
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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.
Bharti
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
Daniel
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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Berger describes sociologists as concerned with
Mueller 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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