1. C-Character Set Dept. of Computer Applications Prof. Harpreet Kaur
Govt College Dera Bassi

2. C-Character Set
It is a set of all the alphabets, digits and special symbols used in C language which are:
Alphabets – A to Z, a to z
Digits – 0 to 9
Special symbols - , . ; # $ % { } etc

3. TOKENS
When the compiler is processing the source code of a C program, each group of characters separated by white space is called as a token.
A token is source program text that the compiler does not break down into separate elements.

4. IDENTIFIERS
Both uppercase and lowercase letters can be used but have different meaning.
Eg. : Area, average, sum, SUM, MARKS, M5.e6 etc, are all valid identifiers, whereas 6th, basic- pay, d.a, h-r-a, t a are invalid identifiers because they all have invalid character in it.

5. IDENTIFIERS
They have same rules to construct as the rules for constructing variables names.
IDENTIFIERS are the names given to various elements of program such as variables, functions, arrays,unions etc.