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26 capital letter of English alphabet : A, B, C, D, . . . . X, Y, Z

26 small letter of English alphabet : a, b, c, d, . . . .x, y, z

10 digits : 0, 1, . . . 9

Math operators : + - * / =<>

Other symbols : |, \, # , %, ~, . . . .

Key words

A keyword is an identifier which indicate a specific command. Keywords are also considered reserved words. You shouldn’t use them for any other purpose in a C program.

The most important keywords of Turbo C are

asm auto break case char const continue default
do double else enum extern float for goto
if int long register return short signed sizeof
static struct switch typedef union unsigned void volatile
while

Identifiers

Identifiers or names refer to a variety of things : functions; tag of structures, union and enumerations; member of structures or unions; enumeration constants; typedef names and objects. There are some restrictions on the names .

Names are made up of letters and digit; The first character must be a letter. The underscore “_” count as a letter; sometime it is useful for improving the readability of long variable names. For example, name unit_price is easier to understand than unitprice . However, don’t begin variable names with underscore, since library routines often use such names.

Upper and lower case are distinct, so x and X are different names. Traditional C practice use lower case for variable names, and all upper case for symbolic constant.

Only the first 31 characters are significant.

Keywords are reserved: you can’t use them as variable names.

Example The following names are valid

i, x, b55, max_val

and the following names are invalid

12w the first character is a digit
income tax use invalid character “ “
char char is a keyword

It is wise to choose variable names that are related to the purpose of the variable, for example, count_of_girls, MAXWORD.

Data types

Data is valuable resources of computers. Data may comprise numbers, text, images . . .

They belong to different data types.

In programming languages, a data type is a set of values and the operations on those values.

For example, int type is the set of 32-bit integers within the range -2,147,483,648 to 2,147,483,647 together with the operations described in the following table.

Operations Symbol
Opposite -
Addition +
Subtraction -
Multiplication *
Division /
Modulus %
Equal to = =
Greater than >
Less than <

A data type can also be thought of as a constraint placed upon the interpretation of data in a type system in computer programming.

Common types of data in programming languages include primitive types (such as integers, floating point numbers or characters), tuples, records, algebraic data types, abstract data types, reference types, classes and function types. A data type describes representation, interpretation and structure of values manipulated by algorithms or objects stored in computer memory or other storage device. The type system uses data type information to check correctness of computer programs that access or manipulate the

data.

Constants

In general, a constant is a specific quantity that does not or cannot change or vary. A constant’s value is fixed at compile-time and cannot change during program execution. C supports three types of constants : numeric, character, string.

Questions & Answers

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
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 ?
s.
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.
Virgil
is Bucky paper clear?
CYNTHIA
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
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
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
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
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
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
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit 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, Introduction to computer science. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10776/1.1
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