Std 10 computer chapter 10 introduction to c language (part2) by Nuzhat Memon C Character Set C Tokens Keywords Identifier Variable Constants

1. Presented by Nuzhat Memon
Chapter 10
Introduction to C Language
(PART 2 C Character set & C Tokens)
Presented by: Nuzhat Memon

2. Presented by Nuzhat Memon
Agenda
2
Alphabet
--------------
Digits
--------------
White spaces
--------------
Special Symbols
keywords
--------------
identifiers
--------------
variables
--------------
Constants
--------------
Strings
--------------
Operators
--------------
Special characters
Instructions Program
character set
C Token
Alphabets words sentences

3. Presented by Nuzhat Memon
C Character Set
Each language has its
alphabets which can be used to
form words and sentences.
So does c language has its own
character set.
.
3

4. Presented by Nuzhat Memon 4
Blank space
Horizontal tab
Vertical tab
New line
Form feed
0 1 2 3 4 5 6 7 8 9
A …Z
a…z
C Character Set
Letters Digits White Spaces Special Characters
Comma ,
Semi colon ;
Colon :
Quotation mark “
Period .
Apostrophe ′
Question mark ?
Ampersand &
At the rate @
Dollar $
Hash sign #
Tilde ~
Underscore _
Exclamation !
Greater than >
Less than <
Equal to =
Plus +
Minus -
Percent %
Asterisk *
Forward slash /
Backward slash
Vertical bar |
Caret ^
Parenthesis ()
Curly braces {}
Square bracket []

5. Presented by Nuzhat Memon
C Tokens
Tokens are Smallest
individual units in a C
program.
C is basically identifies six
types of token.
.
5

6. Presented by Nuzhat Memon 6
C Tokens
Keyword Identifier Constant String Operator Special
character
Constants are
values that remain
unchanged during
the program
execution
Example: 3.14, 10,
-2.5
# <> {} ()
[] , . ;
+ - * / % > < =
Predefined or
reserved words
Example: float,
int, char, if …
User defined names
given to variable,
function or
symbolic constants
Example: pi, diff,
main, interest …
Sequence of
characters enclosed
in double quotes “”
which end with
null character ‘0’
“hello” 
{‘H’, ’e’, ’l’, ’l’, ‘o’}
#include<stdio.h>
void main()
{
int qty=10;
printf(“hello”);
}
# | include | < | stdio | . | h | > |
void | main | ( | ) |
{ |
int | qty | = | 10 | ; |
printf | ( | “hello” | ) | ; |
} |

7. Presented by Nuzhat Memon
KeyworDS
7
 Each Keyword has a predefined meaning
 ANSI C standard supports 32 predefined words
auto double int struct
break else long switch
case enum register typedef
char extern return union
const float short unsigned
continue f0r signed void
default goto sizeof volatile
do if static while

8. Presented by Nuzhat Memon 8
IDENTIFIER
 User defined names given by user to variable,
function or symbolic constant for the purpose of
identification
 A word that a user can construct by making use
of C character set is known as identifier
 It consists of set of letters(totalcost),
digits(totalcost1), underscore(total_cost)
 Example: pi, qty, total, principal, interest, main,
difference
Rule 1: The First character of
variable name must be a letter or
underscore (totalcost, _totalcost)
Rules 2: No Special Character
Variable name consists of
• Letter (a-z, A-Z)
• Digit (0 -9)
• Underscore (_)
Rule 3: No Keywords - Keyword
cannot be used as a variable name.
Rule 4: Maximum length of variable
name as per ANSI standards is 31
characters.
Rule 5: Case sensitive .. Total, total,
TOTAL all are different 10

9. Presented by Nuzhat Memon 9
VARIABLE
 A variable is basically a data name that is used to store values.
 The data within the memory space is referred by a name known as variable
 Unlike constants that remain unchanged during the program execution, a variable can
vary and take up several values during the program execution.
Cell Address/Memory location
10
name
int a=10;
variable
value
10
a
a=a+1;
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10. Presented by Nuzhat Memon
Exercise
10
Valid (Yes)
Invalid (No)
Reason
Total Value No Blank space is not allowed
total&value No Special character is not allowed
total_value Yes Underscore is allowed
_file Yes First character can be underscore
10marks No First character has to be letter or underscore
mark100 Yes As first character is character so it is allowed
char No Use of reserved keyword not allowed
Double Yes
Identifiers are case sensitive, so this is not same as
keyword double
INTEREST Yes Capital and small letters are part of C character set

11. Presented by Nuzhat Memon 11
Constants
Single
Character
String
Base 10
(0-9)
75, -99
Decimal Hexadecimal
Octal
2,000
10.55
abcd
Base 16
0x or 0X
(0-9, A-F)
0X75, 0xA
A B C D E F
10 11 12 13 14 15
Base 8
(0-7)
075, -63
096
Integer
Whole numbers
Real
Decimal numbers with
fractional part ‘a’, ‘#’, ‘3’
sequence of
characters
enclosed in “ “
“hello”, “a”
41.5
25.75
0.2575 e 2
Mantissa exponent
Escape character
a : Audible alert
b : Backspace
f : Form feed
n : New line
r : Carriage return
t : Horizontal tab
v: Vertical tab
’ : Single quote
” : Double quote
? : Question mark
: Backslash
0: Null
#define PI 3.14
#define MAX 10
Numeric Special
Character
Character Symbolic
Constant
‘a’ ‘b’ ‘c’ …. ‘z’
97 98 99 … 122
‘A’ ‘B’ ‘C’ … ‘Z’
65 66 67 … 90
0 1 2 … 3
48 49 50 … 57

12. Presented by Nuzhat Memon
Thanks for Watching
12
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nuzhat.memon@gmail.com