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The procedure for doing that is as follows:

  • Open the code visualizer .
  • Copy the example program code into the online text editor .
  • Select Python 3.3 in the pull-down list.
  • Click the button labeled Visualize Execution .
  • Use the Forward and Back buttons to step forward and backward through your code, one instruction at a time,while observing the positions of the red and green arrows and observing the information that appears on the screen to the right of the code window.

Discussion and sample code

The earlier module titled Itse1359-1060-Syntax in this book presented and explained the two Pythonprograms shown in Listing 1 and Listing 2 . I will illustrate the use of the code visualizer with this pair of sample programs.

Listing 1. A sample program with proper indentation.
A = 3 B = 4if B>A: print(A) # begin groupprint(B) print(A + B) # end groupA = 6 # not part of above group print(A)
Listing 2. Another sample program with proper indentation.
A = 4 B = 3if B>A: print(A) # begin groupprint(B) print(A + B) # end groupA = 6 # not part of above group print(A)

Open the online text editor

When you first open the online text editor , a portion of the screen will look like Figure 1 .

Figure 1. The online text editor.

missing image

The blank portion at the top of Figure 1 is the text editor portion of the screen.

Three drop-down boxes

There are three drop-down boxes at the bottom of Figure 1 that allow you to selectdifferent options. The different options in these boxes control the manner in which the output information is presented as youstep through the program. In some cases, you might want to step through the same program more than once with different sets of options selected.

Beginning the visualization process

Figure 2 shows the result of pasting the code from Listing 1 into the text editor and pressing the button in Figure 1 labeled Visualize Execution .

Figure 2. Beginning the visualization process.

missing image

The red and green arrows

As indicated by the key in the bottom left corner of Figure 2 , two arrows will appear next to the code as you step through the code. A redarrow shows the instruction that will be executed the next time you press the Forward button. (Pressing the Back button moves the red arrowback one step.) The green arrow shows the instruction that was most recently executed. (The green arrow isn't visible in Figure 2 because it is underneath the red arrow at the beginning.)

Output following three presses of the Forward button

Figure 3 shows the result of pressing the Forward button three times.

Figure 3. Output following three presses of the Forward button.

missing image

We see from the green arrow on the left that the relational test in the if statement was the most recently executed instruction.

We see on the right that the variables named A and B contain references (pointers) to objects of type int containing values of 3 and 4 respectively.

Because B is greater than A , the relational test in the if statement (pointed to by the green arrow) returned true when that statement was executed. This means that the threestatements in the indented block following the if statement will be executed. The red arrow points to the first statement in the indented blockmeaning that it will be executed the next time the user presses the Forward button.

Questions & Answers

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
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
Devang Reply
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
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Itse 1359 introduction to scripting languages: python. OpenStax CNX. Jan 22, 2016 Download for free at https://legacy.cnx.org/content/col11713/1.32
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