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Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the imageswhile you are reading about them.

Images

  • Image A . Pseudocode for the program named ForeverLoop01.
  • Image B . Program code for the Scratch v1.4 version of the program named ForeverLoop01.
  • Image C . Program code for the Scratch v2.0 version of the program named ForeverLoop01.
  • Image D . Comparison between repeat and forever/if blocks.
  • Image E . Program code for the program named ForeverLoop02.
  • Image F . Pseudocode for the program named ForeverLoop02.
  • Image G . Pseudocode for the program named RepeatUntil01.
  • Image H . Program code for the program named RepeatUntil01.
  • Image I . Final screen output from the program named RepeatUntil01.
  • Image J . Blocks that can be used to create loop structures in v2.0.

General background information

In an earlier module, I told you that any programming logic problem could be solved using an appropriate combination of only three programming structures,none of which are complicated. The three structures are known generally as:

  • The sequence structure.
  • The selection or decision structure.
  • The loop, repetition, or iteration structure.

I have explained the sequence and selection structures and some of the loop structures in earlier modules. I will continue to concentrate on the loopstructure in this module.

Preview

In this module, I will present and explain the following three Scratch programs:

  • ForeverLoop01 - This program uses a forever block in conjunction with an if block to cause a sprite to move in a small circle while the space bar is pressed.
  • ForeverLoop02 - This program illustrates the creation of a counter loop using a forever block in conjunction with an if block.
  • RepeatUntil01 - This program uses a repeat until block to cause a sprite to run in a small circle until the user presses the spacebar.

In addition, I will provide the specifications for a student-programming project for you to demonstrate your understanding of what you learned from thethree programs listed above and from earlier modules.

Discussion and sample code

The program named ForeverLoop01

This program illustrates the use of a forever block in conjunction with an if block. When the user clicks the green flag, the program implements the pseudocode shown in Image A .

Image a. pseudocode for the program named foreverloop01.

Move the cat to the center of the stage. Turn the cat to face to the right.while(true){//infinite loop if(space bar is pressed){Change cat to next costume image Move cat forward 10 steps.Wait 0.1 seconds. Turn cat clockwise 15 degrees.}//end if statement }//end infinite while loop
Image A. Pseudocode for the program named ForeverLoop01.

If the space bar is pressed, the cat moves around the circumference of a small circle, appearing to walk due to the visual effect produced by switchingbetween two images (known in Scratch as costumes) . As explained in a previous module,the two costumes were designed to produce the illusion of walking.

Program code for the Scratch v1.4 version of the program named ForeverLoop01

The code for the older Scratch v1.4 version of this program is shown in Image B .

Image b. program code for the scratch v1.4 version of the program named foreverloop01.

Missing image.
Image B. Program code for the Scratch v1.4 version of the program named ForeverLoop01.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
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
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
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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