Keywords
- Keywords are preserved words that have special meaning in C language.
- The meaning has already been described.
- These meaning cannot be changed.
- There are total 32 keywords in C language.
| 32 ANSI C Keywords |
| auto |
double |
int |
struct |
| break |
else |
long |
switch |
| case |
enum |
register |
typedef |
| const |
extern |
return |
union |
| char |
float |
short |
unsigned |
| continue |
for |
signed |
volatile |
| default |
goto |
sizeof |
void |
| do |
if |
static |
while |
Identifiers
In C language identifiers are the names given to variables, constants, functions and user-define data. These identifier are defined against a set of rules.
Rules for an Identifier
- An Identifier can only have alphanumeric characters ( a-z , A-Z , 0-9 ) and underscore( _ ).
- The first character of an identifier can only contain alphabet( a-z , A-Z ) or underscore ( _ ).
- Identifiers are also case sensitive in C. For example name and Name are two different identifier in C.
- Keywords are not allowed to be used as Identifiers.
- No special characters, such as semicolon, period, white spaces, slash or comma are permitted to be used in or as Identifier.
Character set
In C language characters are grouped into the following categories,
- Letters (all alphabets a to z & A to Z).
- Digits (all digits 0 to 9).
- Special characters ( such as colon
:, semicolon ;, period ., underscore _, ampersand & etc).
- White spaces.
Ask Question