The individual elements of a program are called Tokens. There are following 6 types of tokens are available in C:
Keywords : Keywords are predefined, reserved words used in programming that have special meanings to the compiler. Keywords are part of the syntax and they cannot be used as an identifier. As C is a case sensitive language, all keywords must be written in lowercase. There are 32 keywords in c. For example: int money; Here, int is a keyword that indicates money is a variable of type int (integer).
Identifiers : identifiers are names given to different entities such as constants, variables, structures, functions, etc. Identifier names must differ in spelling and case from any keywords. You cannot use keywords (either C or Microsoft) as identifiers; they are reserved for special use. for example: int amount; double totalbalance; In the above example, amount and totalbalance are identifiers and int, and double are keywords.
Constants : A constant is a name given to the variable whose values can’t be altered or changed. A constant is very similar to variables in the C programming language, but it can hold only a single variable during the execution of a program.
Strings : In C programming, a string is a sequence of characters terminated with a null character \0. Strings are defined as an array of characters. The difference between a character array and a string is the string is terminated with a special character ‘\0’.
Special Characters : In C programming language, generally, the special symbols have some special meaning and they cannot be used for other purposes.
Some of the special symbols that are [] () {}, ; * = #
Operators : An operator is a symbol which operates on a variable or value. C language is rich in built-in operators and provides the following types of operators
–Arithmetic Operators
–Relational Operators
–Logical Operators
–Bitwise Operators
–Assignment Operators
–Misc Operators
Note: Some special types of operators are also present in C like sizeof(), Pointer operator, Reference operator etc.