C language Character Set
In C language you can use the following characters.
Alphabets
|
1 2 |
a, b, c, ... z A, B, C, ... Z |
Digits
|
1 |
0,1,2,3,4,5,6,7,8,9 |
Special Symbols
The following table shows some special characters used extensively in C.
| Character | Meaning |
|---|---|
+ |
Plus Sign |
- |
Minus Sign |
* |
Multiplication |
/ |
Division |
% |
Percent Sign or modulus operator |
() |
Parentheses |
{} |
Curly braces |
[] |
Square brackets |
= |
Equal Sign |
, |
comma |
; |
Semicolon |
: |
colon |
' |
Single quote |
" |
Double quote |
? |
Question mark |
. |
Period or dot symbol |
# |
Hash |
^ |
Caret symbol |
~ |
Tilde |
! |
Exclamation mark |
& |
ampersand |
| |
pipe character |
Escape Sequences
Escape Sequences are used to print some special characters which can’t be printed directly using the keyboard. For example, newline, tab, carriage return etc. An Escape Sequences consists of a backslash character (\) followed by a particular escape character. The following table lists common escape sequences.
| Escape Sequence | Meaning | What it does? |
|---|---|---|
\n |
newline | Moves the cursor to the beginning of the next line. |
\t |
tab | Moves the cursor to the next tab stop. |
\b |
backspace | Moves the cursor back by one space on the current line. |
\r |
carriage return | Moves the cursor to the beginning of the current line. |
\a |
bell (alert) | Produces a beep sound. |
\\ |
backslash | Prints the backslash (\) character. |
\0 |
null | \0 character denotes a null character. |
\' |
single quote | Prints the single quote (') character. |
\" |
double quote | Prints the double quote (") character. |
Note: newline (\n), backspace (\b), Carriage return (\r), tab (\t), space ( ) are known as whitespace characters.
Keywords
Keywords are some reserved words that C language use for denoting something specific. In C, Keywords are written in lowercase. C has only 32 Keywords.
Identifiers
Identifiers are the words we use to name entities like variables, functions, array, structure, symbolic constant etc.
The rules for naming identifiers are as follows:
- Identifiers must consist of alphabets, digits or underscores (
_) only. - The first character should be an alphabet or underscore (
_). - The identifier should not be a keyword.
- Identifiers can be of any length.
C is case-sensitive language so my_var and MY_VAR are two distinct identifiers.
Some examples of valid identifiers:
num , _address , user_name , email_1
Examples of invalid identifiers:
1digit – an identifier must not start with a number
my var – an identifier must not contain a space character
int – int is a keyword
some# – pound (#) character is not allowed
Quiz - C Keywords and Identifiers
Test your knowledge about C Keywords and Identifiers
thanks bro