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C Programming - Constants and Variables

 

C Programming - Constants and Variables

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C Programming Language - Constants and Variables

In this tutorial you will learn about Character Set, C Character-Set Table, Special Characters, White Space, Keywords and Identifiers, Constants, Integer Constants, Decimal Integers, Octal Integers, Hexadecimal integer, Real Constants, Single Character Constants, String Constants, Backslash Character Constants [Escape Sequences] and Variables.



Instructions in C language are formed using syntax and keywords. It is necessary to strictly follow C language Syntax rules. Any instructions that mis-matches with C language Syntax generates an error while compiling the program. All programs must confirm to rules pre-defined in C Language. Keywords as special words which are exclusively used by C language, each keyword has its own meaning and relevance hence, Keywords should not be used either as Variable or Constant names.


Character Set

The character set in C Language can be grouped into the following categories.


1. Letters
2. Digits
3. Special Characters
4. White Spaces


White Spaces are ignored by the compiler until they are a part of string constant. White Space may be used to separate words, but are strictly prohibited while using between characters of keywords or identifiers.


C Character-Set Table

Letters


Digits


Upper Case A to Z


0 to 9


Lower Case a to z


.


Special Characters


,


.Comma


&


.Ampersand


.


.Period


^


.Caret

;


.Semicolon


*


.Asterisk


:


.Colon


-


.Minus Sign


?


.Question Mark


+


.Plus Sign


'


.Aphostrophe


<


.Opening Angle (Less than sign)


"


.Quotation Marks


>


.Closing Angle (Greater than sign)


!


.Exclaimation Mark


(


.Left Parenthesis


|


.Vertical Bar


)


.Right Parenthesis


/


.Slash


[


.Left Bracket


\


.Backslash


]


.Right Bracket


~


.Tilde


{


.Left Brace


-


.Underscore


}


.Right Bracket


$


.Dollar Sign


#


.Number Sign


%


.Percentage Sign . .


 


 


 


 


 


 


 


 


 


 


.

.
.
White Space

1. Blank Space
2. Horizontal Tab
3. Carriage Return
4. New Line
5. Form Feed


Keywords and Identifiers


Every word in C language is a keyword or an identifier. Keywords in C language cannot be used as a variable name. They are specifically used by the compiler for its own purpose and they serve as building blocks of a c program.


The following are the Keyword set of C language.


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


some compilers may have additional keywords listed in C manual.


Identifiers refers to the name of user-defined variables, array and functions. A variable should be essentially a sequence of letters and or digits and the variable name should begin with a character.


Both uppercase and lowercase letters are permitted. The underscore character is also permitted in identifiers.


Next Page: C Programming - Constants and Variables - Page 2


Read Next: C Programming Language - Data Types



 

 

Comments


Amit Anjan said:

  ;)hey the content is superb..its too good for the beginners..
August 27, 2006, 9:12 am

Thilina said:

  I really think all this is so incredible coz it is so simple to understand. Now i can bunk classes but still have hope.
Thanks
January 23, 2008, 2:36 pm

Aaj said:

  Hi,
i am beginner and want more explanation,please provide
November 6, 2008, 5:17 am

preeti said:

  the content is fabulus
November 13, 2008, 10:41 am

lalu said:

  i would like to know how to produce a new product by using

c progrmming and vectors and matrices
December 12, 2008, 12:02 am

satheesh.s said:

  hai, i am satheesh ,i am doing mca,these simply enough for beginners ,i want to know the source code for printf and scanf fuctions.
December 22, 2008, 12:21 am

Raman Bhatia said:

  Hi, This is Raman Bhatia From Punjab , its contents too simple that i want to appriciate to the Writer, its too fabulous
December 26, 2008, 1:04 am

Anuj said:

  I really think all this is so incredible coz it is so simple to understand. Now i can bunk classes but still have hope.
January 31, 2009, 5:41 am

Sonu Bhadouria said:

  Its very necessery for the beginner.
February 8, 2009, 12:29 pm

bharathi said:

  i need help to find error
February 9, 2009, 7:31 am

murari said:

  I really have interest for learning the C programming. When the function portion comes, I really confuse. How I can remove it.
thank u
February 13, 2009, 6:04 am

shoujoreader said:

  what kind of error? logical or syntax errors?
logical errors are more hard to debug...

Experts say, programmers are intellectual.
I agree, it's hard to study C programming, it takes a lot time and effort. Maybe because the teaching in our school is hard.
August 21, 2009, 12:14 am

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