The document discusses different types of constants and variables in C programming. It describes integer, real, character, and string constants. Integer constants can be decimal, octal, or hexadecimal. Real constants represent quantities that vary continuously, with a mantissa and exponent. Character constants contain a single character within single quotes. String constants contain a sequence of characters within double quotes. Variables are names that store changing data values during program execution, while constants remain unchanged. Variables must start with a letter and can contain letters, digits, and underscores.

1. YASH
CONSTANT AND
VARIACLES
IN C
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2. CONSTANT
CONSTANTS
NUMERIC CHARACTER
INTEGER REAL
STRING
CHARACTER
SINGLE
CHARACTER
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3. INTEGER CONSTANT
• IT IS REFERS TO A SEQUNCE OF DIGITS
• THERE ARE THREE TYPES :-
(1) DECIMAL INTEGER
(2) OCTAL INTEGER
(3) HRXADECIMAL INTEGER
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4. • (1):- DECIMAL INTEGERS CONSIST OF A SET OF
DIGITS, O THROUGH 9, PRECEDED BY AN OPTIONAL
- OR + SIGN.
EX= 123 -321 0 654321 +78
EMBEDDED SPACES, COMMAS, AND NON DIGIT
CHARACTERS ARE NOT PERMITTED BETWEEN DIGTS.
EX= 15 750 20000 $1000
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5. • (2):- AN OCTAL INTEGER CONSTANT CONSIST OF ANY
COMBINATION OF DIGITS FROM THE SET 0 THROUGH 7,
WITH A LEADING 0.
EX = 037 0 0435 O551
• (3):- A SEQUENCE OF DIGITS PRECEDED BY 0X IS
CONSIDERD AS HEXADECIMAL INTEGER. THEY MAY ALSO
INCLUDE ALPHABETS A THROUGH F OR A THROUGH F
REPRESENT THE NUMBERS 10 THROUGH 15…
EX = 0X2 OX9F OXbcd 0x
We rarely use octal and hexadecimal numbers in
programming http://alltypeim.blogspot.in/

6. REAL CONSTANT
• INTEGER NUMBER ARE INADEQUATE TO REPRESENT
QUANTITES THAT VERY CONTINUOUSLY ,SUCH AS AS
DISTANCES,HEIGHTS,TEMPERTURES,PRICES AND SO
ON..SUCH NUMBERS ARE CALLED REAL CONSTANTS..
EX= 0.0083 -O.75 435.36 +247.0
• The mantissa is either a real number expressed in
exponential notation an integer. The letter separating the
mantissa and the exponent can be written in either lower
case or upper case .
ex= 0.65e4 12e-2 1.5e+5http://alltypeim.blogspot.in/

7. • Example of numeric consatant
Constant valid?? Remarks
698354L yes represent long integer
2500 no comma is not allowed
+5.0E3 yes (ANSI C supports unary
plus)
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8. SINGLE CHARACTER CONSTANT
• A SINGLE CHARACTER CONSTANT COTAINS A SINGLE
CHARACTER ENCLOSED WITHIN APAIR OF SINGLE QUOTE
MARKS .
EX= ‘5’ ‘X’ ‘;’ ‘ ’
• note that the character constant 5 is not the same as the
number 5
printf(“%d”, ’a’ );
Would print the number 9, the ASCII value of the letter a.
• Since each character constant represents an integer value
it is also possible perform arithmetic operations
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9. Single constant
• A sting constant is a sequence of characters
enclosed in double quotes. The character may be
letters , numbers, special character and blank space
are ex =“hello!” “1987 “
• Remember that a constant is not equivalent to the
single string constant . Character strings are often
used in programs to build meaningful programs
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10. BACKSLASH CHARACTER
• C supports some special backslash character that
are used in output function . For example ,the
symbol ‘n’ stands for newline character.
• Note that each one of them represents one
character , although they consist of two
characters.
• these characters combinations are know as escape
sequence
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11. • CONSTANT MEANIG
a audible alert
b back space f
form feed
n new line
r carriage return
t horizontal tab
v vertical tab
‘ ” single quote
‘ “’ double quote
? question bank
back slash
0 null
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12. VARIBLES
• A variable is a data name that may be used to store
data value. Unlike constant that remain unchanged
during the execution of a program ,a variable take
different values at different times during execution.
• a variable name can be chosen by the programmer
in a meaningful way so as to reflect its function or
nature in the program ..some example
average counter_1
height class_strength
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13. • As mentioned earlier ,variable , names may consist
of letters ,digits and the underscore (_) character ,
subject to the following conditions;
(1) They must begin with a letter .some systems
permit underscore as the first character.
(2) ANSI standard recognizes a length should not be
normally more than eight characters since only the
first eight characters are treated as significant by
many compilers
(3) Uppercase and lowercase are significant. That is
,the variable Total is not the same as total or
TOTAL http://alltypeim.blogspot.in/

14. (4) It should not be a keyword.
(5) White space is not allowed
• Examples of variable names
variable name valid ?? Remark
first_tag valid
char not valid chair is a
keyword
Int _type valid keyword may
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15. • If only the first eight characters are recognized by a
compiler ,then the two names
average_height
average_weight
mean the same thing to the computer such names
can be rewritten as
avg_height and avg_weight
ht_average and wt_average
With out changing their meaningshttp://alltypeim.blogspot.in/

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