Keywords and Identifiers
C language character set #
In C language you can use the following characters.
a, b, c, ... z A, B, C, ... Z
The following table shows some special characters used extensively in C.
|%||Percent Sign or modulus operator|
|.||Period or dot symbol|
Escape Sequences #
Escape Sequences are used to print some special characters in the console which can't be printed by directly using the keyboard such as newline, tab etc. Escape Sequences consists of 2 or more characters, the first character is
\ and the second character varies according to the need. Here are some common escape sequences.
|Escape Sequence||Meaning||What it does ?|
Note: newline (
\n), backspace (
\b), Carriage return (
\r), tab (
\t), space (
) are known as whitespace characters.
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 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 (
- 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 are two distinct identifiers.
Some examples of valid identifiers:
Examples of invalid identifiers:
1digit – an identifier must not start with a number
my var – an identifier must not contain space between names
int is a keyword
some# – pound(
#) character is not allowed