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Six blocks have the correct shape

As you can see in Image 4 , there are six blocks of the correct shape exposed by clicking the Operators button. Those blocks are identified as follows:

<(less than) = (equal to)>(greater than) andor not

We will refer to the first three blocks above as relational operators . (They are used to evaluate the relationship between two values.) We will refer to the other three blocks in the above list as logical operators , and will deal with them in a future module.

Relational operators in other languages

Many other modern programming languages also include the following three relational operators:

>= (greater than or equal)<= (less than or equal) != (not equal)

Although these operators are a great convenience, they are not essential. We can get by with only the three that are provided by Scratch.

Also, in many other programming languages, a pair of equal characters (==) is used for the equal to operator instead of the single equal character (=) used in Scratch.

Three steps at once

Image 5 shows the result of having taken three more steps in the development of the program:

  1. I dragged the green less than (indicated by a left angle bracket) block and dropped it into the pocket immediately to the right of the word if .
  2. I dragged the orange block labeled set...to for the variable named LessThan and inserted it immediately below the word if . I also set its literal value to 1.
  3. I dragged another copy of the orange block labeled set...to for the variable named LessThan and inserted it immediately below the word else . I left its literal value as the default value of zero.

Image 5. intermediate stage in construction of if-else script.

Missing image
Image 5. Intermediate stage in construction of if-else script.

Still need to complete the conditional clause

The script in Image 5 includes the action to be taken if the relational expression following the word if evaluates to true. It also includes the action to be taken if therelational expression evaluates to false. (This relational expression is often referred to as a conditional clause.) .

However, we still haven't completed the conditional clause in Image 5 . We don't want to test for the relationship between theliteral values blank and blank as shown in Image 5 . Instead we want to test the relationship between the values of the variablesnamed LeftOperand and RightOperand as shown in the corresponding script in Image 2 .

Complete the relational expression

The next and final step for constructing this script is to:

  • Click the Variables button to expose the variables as shown in Image 1 .
  • Drag the block for the variable named LeftOperand and drop it in the white box immediately to the left of the left angle bracket operator in Image 5 .
  • Drag the block for the variable named RightOperand and drop it in the white box immediately to the right of the left angle bracket operator in Image 5 .

Once we do that, we will have finished the construction of the second script from the top in Image 2 .

Completing the program

Following that, we need to go through essentially the same process to construct the bottom two scripts in Image 2 , using the other two relational operators in Image 4 along with the variables named LeftOperand and RightOperand .

Questions & Answers

Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
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.
Harper
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
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
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
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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