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Same situation, different code

Figure 4 shows the same situation using the code from Listing 2. instead of the code from Listing 1 .

Figure 4. Same situation, different code.

missing image

Note that the values stored in the variables named A and B were reversed relative to the code in Figure 3 . As a result, the if statement pointed to by the green arrow returned false instead of true when that statement was executed. Because of that, execution ofthe indented code block following the if statement will be skipped entirely and the red arrow now points to the statement immediately following that code block.That is the next statement that will be executed.

Stepping through the code

As you use the Forward and Back buttons to step through the code, one instruction at a time, you can observe the red and green arrows to gain a betterunderstanding of the flow of control through the program. (You will learn more aboutflow of control in future modules and you will probably find that the code visualizer is particularly useful when analyzing that code.)

If you are in a hurry, you can press the First button and the Last button to cause the code visualizer to go the first or last instruction in one step.

The student torture program

There are links to quite a few sample programs below the drop-down boxes shown in Figure 1 . (I cropped them out of Figure 1 to save space.) One of those sample programs is named student torture .

As a preview of things to come, Figure 5 shows the result of opening that program in the code visualizer and pressing the Last button.

Figure 5. The student torture program.

missing image

Sharing the code visualizer with a tutor

Finally, there is another interesting sample program at (External Link) that you can step through and observe its behavior. While you are there, be sure to note your ability to share the code visualizer with a friend or a tutor on anothercomputer on the Internet and jointly analyze a program.

Run the programs

I encourage you to use the code in Listing 1 and Listing 2. along with the code visualizer to repeat theprocedures explained in this module. Confirm that you get results similar to those shown in Figure 3 and Figure 4 .

Change the options in the drop-down boxes and observe the results.

Experiment with the code, making changes, and observing the results of your changes. Make certain that youcan explain why your changes behave as they do.

As mentioned earlier, I strongly recommend that from this point forward in this course, you copy and paste every sample program into the code visualizerand observe the behavior of that code as you step through the program, one instruction at a time. I believe that doing that will help you to betterunderstand Python programming.


This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Itse1359-1065-Visualizing Python
  • File: Itse1359-1065.htm
  • Published: 01/31/16

Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.


Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
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.
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
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
characteristics of micro business
for teaching engĺish at school how nano technology help us
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
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
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.
what is the actual application of fullerenes nowadays?
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.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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