# 1.3 Scr0330: sequence, selection, and loop in scratch 2.0.  (Page 2/9)

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## Images

• Image 1 . The sequence structure in pseudocode.
• Image 2 . The selection structure in pseudocode.
• Image 3 . The loop structure in pseudocode.
• Image 4 . Scratch 2.0 programming interface for the program named IfSimple01.
• Image 5 . A paraphrased version of the Scratch code.
• Image 6 . Program code for the left beachball
• Image 7 . Initializing the position and orientation of the basketball.
• Image 8 . All of the code that applies to the basketball.
• Image 9 . Pseudocode for a selection structure.
• Image 10 . Two independent decisions.
• Image 11 . Control structures available in Scratch.
• Image 12 . Programming blocks belonging to the Sensing group.
• Image 13 . Initial output from the program named IfWithVar01.
• Image 14 . Program output after having clicked twice in the Stage area.

## General background information

• Structured programming.
• The sequence structure.
• The selection structure.
• The loop structure.

In introductory programming courses, you will often hear a lot about something called structured programming. In comparison with more modern and complex programming concepts such as runtime polymorphism, structured programming is fairly mundane. However, that's not to say that structured programming isn'timportant. It is very important. But it is just a small bump in the road of learning that leads to a more complete understanding of computerprogramming, especially object-oriented programming.

## What is structured programming ?

Basically, the concept of structured programming says that any programming logic problem can be solved using an appropriate combination of only threeprogramming 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.

## One door in and one door out

To understand structured programming, you need to think in terms of a section of program code that has only one entry point and one exit point. It isvery important that there cannot be multiple entry points or multiple exit points.

There must be only one way into the section of code and one way out of the section of code.

## Nesting of structures is allowed

Another important part of the concept is that structures may be nested inside of other structures provided that every structure meets the basic rules for astructure.

Thus, by nesting simple structures inside of simple structures, large and complex overall structures can be constructed.

## Pseudocode

Computer programming source code consists generally (but not in Scratch) of programming instructions written in text form with a very specific format or syntax that is designed to be understood by a computerprogram. (This is commonly called source code.) Humans who are not computer programmers might not be expected to understand much of what they see in computer programming source code.

According to Wikipedia ,

"The prefix pseudo - (from Greek... "lying, false") is used to mark something as false, fraudulent, or pretending to be something it is not."

Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
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?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
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?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
how did you get the value of 2000N.What calculations are needed to arrive at it
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