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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

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
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
hey
Giriraj
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
ya I also want to know the raman spectra
Bhagvanji
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
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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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