There are 6 characteristics:

• Keywords
• Operators
• Separators
• Constant
• Predefined Functions
• Syntax

Keywords

• Keywords are words that have special meaning to the C compiler.
• An identifier can't have the same spelling and case as a C keyword. We can't use keywords for our own purposes.
• There are a total of 32 keywords in C which are as follows:

Operators

• Special types of symbols i.e. are used to perform specific task
• Types: Binary operator, Unary operator, Ternary operator, etc.
• Total 44 operators are present

Separators:

• Separate things called as a token
• we can separate individual unit -> token

What is Token

The smallest unit of c programming is known as a token. Token can be any keyword, operator, separator, constant, identifier, etc. We can give any number of spaces between tokens.

Constant

• Variable that doesn't change its value throughout the program is known as a constant.
• Types:
  • Alphanumeric constants -> a-z, A-z, 0-9
  • Numeric constants -> 0-9

Predefined Function

• all predefined functions are stored in respective header files.
• e.g.
  • stdio.h -> printf(), scanf(), ...
  • math.h -> sqrt(), ...

Syntax

• Syntax is the rules which need to be followed while developing a program
• e.g. To declare variable syntax is - data_type variable_name ;