A struct (short for “structure”) is very similar to a class and it can contain fields, properties, and methods.
However, structs are value types and are created on the stack.

Note:
You cannot inherit from a struct.
A struct can implement an interface.
structs have limited constructor and destructor semantics.

Why Structs ?
Typically, structs are used to aggregate a relatively small amount of logically related fields.

Structures are declared in the same way as classes.

This example shows what might be the start of a struct for imaginary numbers:

struct ImaginaryNumber{
double real;
public double Real{
get { return real; }
set { real = value; }
}
double i;
public double I{
get { return i; }
set { i = value; }
}
}

..