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An explanation of identifier names including some common rules for the C++ programming language.

Overview

Within programming a variety of items are given descriptive names to make the code more meaningful to us as humans. These names are called "Identifier Names". Constants, variables, type definitions, functions, etc. when declared or defined are identified by a name. These names follow a set of rules that are imposed by:

  1. the language's technical limitations
  2. good programming practices
  3. common industry standards for the language 

Technical to language

  • Use only allowable characters (for C++ the first character alphabetic or underscore, can continue with alphanumeric or underscore)
  • Can't use reserved words
  • Length limit

These attributes vary from one programming language to another. The allowable characters and reserved words will be different. The length limit refers to how many characters are allowed in an identifier name and often is compiler dependent and may vary from compiler to compiler for the same language. However, all programming languages have these three technical rules.

Good programming techniques

  • Meaningful
  • Be case consistent

Meaningful identifier names make your code easier for another to understand. After all what does "p" mean? Is it pi, price, pennies, etc. Thus do not use cryptic (look it up in the dictionary) identifier names.

Some programming languages treat upper and lower case letters used in identifier names as the same. Thus: pig and Pig are treated as the same identifier name. Unknown to you the programmer, the compiler usually forces all identifier names to upper case. Thus: pig and Pig both get changed to PIG. However not all programming languages act this way. Some will treat upper and lower case letters as being different things. Thus: pig and Pig are two different identifier names. If you declare it as pig and then reference it in your code later as Pig – you get a compiler error. To avoid the problem altogether, we teach students to be case consistent . Use an identifier name only once and spell it (upper and lower case) the same way within your program.

Industry rules

  • Do not start with underscore (used for technical programming)
  • variables in all lower case
  • CONSTANTS IN ALL UPPER CASE

These rules are decided by the industry (those who are using the programming language). The above rules were commonly used within the "C" programming language and have to large degree carried over to C++.

Definitions

reserved word
Words that cannot be used by the programmer as identifier names because they already have a specific meaning within the programming language.

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
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
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
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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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