Keywords are the reserved words which convey some special meaning for compiler.
- They cannot be changed or manipulated by user.
- They are case sensitive.
- There are 32 keyword in C
- Identifiers are the name given to the tokens used by a user.
- Token is the smallest unit in program.
- Identifiers are case sensitive.
- They are defined by programmer.
RULES FOR WRITING IDENTIFER:
- It must not be a keyword
- Identifiers can only have alphabets, numbers and an underscore sign( _ ).
- It should not begin with a numbers.
- Identifiers can be any characters long.
Valid Identifiers :
My_name, myname, myNAME, my123, my_123, m12_n32, m1n2 etc.
12Myname, 123, #myname, ?myname, int.