DATA TYPE
Data type mentions the type of data that a variable can store.
C language supports two type of data types:
1. Primary data types:
	These are fundamental data types in C namely integer (int),
	floating point (float), character(char) and void.

2. Derived data types:
	Derived data types are nothing but primary datatypes but a little 
	twisted or grouped together like array, structure, union and pointers.

1. Primary data types:
INT (integer)
Integer datatype accepts only numeric values. 
Its size is 4 bytes and its range is -2,147,483,647 to 2,147,483,647.

Character (char)
char datatype accept only single alphanumeric value.
Its size is 1 byte and its range is -128 to 127

Float:
Float datatype accepts numeric and decimal point values.
Its size is 4 bytes.

Void:
void means no value. This is used to specify the type of functions which
returns nothing.

VARIABLES IN C
Variable is a name which hold a value. Its value can be changeable, 
and it can be reused many times.

RULES OF VARIABLE
* A variable consists of alphabets, digits, and underscore.
* A variable name always start with alphabet or underscore.
* No whitespace is allowed within the variable name.
* A variable name can not be used any reserved word or keyword.
  e.g. int, float, etc.