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Common textbook defining of variables

float length, width, height, price_gal_paint, total_area, total_cost; int coverage_gal_paint, total_gal_paint;

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However common this is in textbooks, it would generally not be acceptable to standards used in most companies. You should declare each item on its own line; like this:

Proper defining of variables with vertical alignment

float length; float width;float height; float price_gal_paint;int coverage_gal_paint; float total_area;int total_gal_paint; float total_cost;

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This method of using one item per line is more readable by humans. It is quicker to find an identifier name, because you can read the list vertically faster than searching horizontally. Some programmers list them in alphabetic order, especially when the number of variables exceeds about twenty.

The lines of code inside either function are also aligned vertically and indented two spaces from the left. The indentation helps set the block off visually.

Appropriate use of comments

You can see through the source code short little comments that describe an area or section. Note the use of input, processing and output which are part of the IPO concept within the program design.

Banners for functions

Note the use of comments in the form of a banner before each function.

Comments as a banner

//****************************************************** // main//******************************************************

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The function name is placed with two lines of asterisks. It makes it extremely easy to find each function definition because you don’t have to read the functions to see where the one ends and the next one begins. You can quickly read the function names within the banners.

Block markers on lines by themselves

Within many languages there is a method to identify a group of programming statements as a unit. With C++ the functions use a set of symbols, the braces {}, to identify a block of code, sometimes referred to as a compound statement. Braces are used in other aspects of programs, but for now we will look at this simple example. These braces have a tendency to cause problems, especially when they don’t have a proper opening brace associated with a proper closing brace. To solve that problem many programmers simply put a brace on a line by itself and make sure the opening brace and closing brace are in the same vertical column.

Indent block markers

A block of code associated with a function or with a control structure is indented two or three spaces. When blocks of code are nested each nesting is indented two or three spaces. In our example above the blocks of code for the function definitions are indented two spaces.

Meaningful identifier names consistently typed

As the name implies "identifier names" should clearly identify who (or what) you are talking about. Calling you spouse "Snooky" may be meaningful to only you. Others might need to see her full name (Jane Mary Smith) to appropriately identify who you are talking about. The same concept in programming is true. Variables, constants, functions, typedefs and other items should use meaningful identifier names. Additionally, those names should be typed consistently in terms of upper and lower case as they are used in the program. Don't define a variable as: Pig and then type it later on in your program as: pig.

Appropriate use of typedef

Many programming languages have a command that allows for the creation of an identifier name that represents a data type. The new identifier name is described or connected to a real data type. This feature is not demonstrated in the code above and is often a confusing concept. It is a powerful way to help document a program so that it is meaningful, but is often used by more experienced programmers.


A method of preserving information useful to others in understanding an information system or part thereof.
vertical alignment
A method of listing items vertically so that they are easier to read quickly.
Information inserted into a source code file for documentation of the program.
A set of comment lines used to help separate the functions and other sections of a program.
Used to identify a block of code in C++.
A method used to make sections of source code more visible.
A rule that says identifier names must be easily understood by another reading the source code.
A rule that says to type identifier names in upper and lower case consistently throughout your source code.

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 ?
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.
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
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what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
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I'm interested in nanotube
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Ramkumar Reply
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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
what is system testing
what is the application of nanotechnology?
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
anybody can imagine what will be happen after 100 years from now in nano tech world
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
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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, Programming fundamentals - a modular structured approach using c++. OpenStax CNX. Jan 10, 2013 Download for free at http://cnx.org/content/col10621/1.22
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