DERIVED DATA TYPES

Long, double,unsigned ,array and pointers are the derived types from the fundamental primitive 
types.A long integer can be declared as follows:

long int i;

or

long  i;

To store a long integer value, four bytes of memory are required.To store the real (float) values more precise, the type double is used.It occupies 8 bytes n the memory.

Unsigned numbers are represented as follows:

unsigned int i;

 unsigned int occupies 2 bytes as normal integers but all the bits are used to store the value.In a regular integer,the most significant bit (the left most bit is a sign bit)