The smallest individual unit in C are known as C-Tokens. The following 6 types are C-Tokens,
1. Keywords (int, float, double, character,...)
2. Identifiers
3. Constants
4. Strings
5. Operators
6. Special Symbols
1. Keywords or Reserved Words:
Keywords are the basic building block for programme statement. Keywords basically sequences of characters that have one or more fixed meanings and these meanings cannot be changed. All keywords must be written in lower case. They are also called Reserved words. These are the names reserved for a very specific and pre-defined purpose. Some of the keywords are listed below;
auto, break, case, char, const, continue, default, do, double, else, enum, extern, float, for, goto, if, int, long, register, return, short, signed, size of, static, struct, switch, typedef, union, unsigned, void, volatile, while..
2. Identifiers:
Identifiers are the names given to the elements such as, Variables, arrays and functions that are used in C Program.
Rules for formatting identifiers name:
1. The first character must be an Alphabetic (Upper case or lower case or under score).
2. All succeeding characters must be either letters or digits.
3. No Special characters or punctuation symbols are allowed except the underscore.
4. No two successive underscores are allowed.
5. Reserved words are should not be used.
3. Constants:
The quantity which does not change its value during the execution of a program is known as Constant.
3.1. Variables:
The quantity which changes its value during the execution of a program called Variable. These are also called as identifiers.
Variables represents a particular memory location where the data can be stored.
4. String:
It is defined as a sequence of characters place between double quotes (" ").
5. Operators:
Operators act as connectors and they indicate what type of operator is been carried out. The values that can be operated by these operators are called as Operands.
