why we generaly use none static members in a class

Static and Instace members can be explained by using a simple example.

In this Example we are calculating the Area of a circle - PI*R*R

using System;
class Circle
{
//PI is declared as static becuase we know that the value of PI will never change.
static float _PI;
//Radius is instance field because static word is not used in below statement.
//We know radius will be different for different areas.
//so radius is declared as an instance field.
int _radius;
//value of PI will be initialized to 3.14 only once and get saved in memory, because below constructor is a static constructor.
static Circle()
{
Circle._PI = 3.14F;
}
//Every time new instance of Circle class will be created then value of radius will be initialized by below constructor hence initialization is done in instance constructor.
public Circle(int radius)
{
this._radius = radius;
}
public float Area()
{
return Circle._PI * this._radius * this._radius;
}
}
class Program
{
static void Main()
{
Circle c1 = new Circle(10);
float area = c1.Area();
Console.WriteLine("Area is {0}",area);
Console.ReadLine();
}
}

If we declare PI as an instance field then whenever we create instance of class Circle as c1 then c1 creates copy of PI and radius fields.

When we create another instance of class Circle as c2 then c2 also creates copy of PI and radius fields.

If we declare PI as an static field then c1 and c2 create copy of only radius field. Because PI has been initialized statically so there will be a single copy of PI and any class can refer to that single copy.so, c1 and c2 also refer to the same copy of PI.

If there will be thousands of objects in future then tey will also refer to that single copy of PI.

Hope this helps to clear the concept.

Regards

Sumit Kushwaha

3 Replies

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Laxmidhar Sahoo9y ago
Accepted answer
Dear sir
Actualy none static memebrs are knowns as instant members of a class.
when the user required the class member he instantieted means allocate
the memory and also if multiple times required then he can.

But static is already remory allocated .No need to allocate the memory
by the user.If the calss memebrs those are not required aslo alocated.
0
Sumit Kushwaha9y ago
Static and Instace members can be explained by using a simple example.
In this Example we are calculating the Area of a circle - PI*R*R
using System;
class Circle
{
//PI is declared as static becuase we know that the value of PI will never change.
static float _PI;
//Radius is instance field because static word is not used in below statement.
//We know radius will be different for different areas.
//so radius is declared as an instance field.
int _radius;
//value of PI will be initialized to 3.14 only once and get saved in memory, because below constructor is a static constructor.
static Circle()
{
Circle._PI = 3.14F;
}
//Every time new instance of Circle class will be created then value of radius will be initialized by below constructor hence initialization is done in instance constructor.
public Circle(int radius)
{
this._radius = radius;
}
public float Area()
{
return Circle._PI * this._radius * this._radius;
}
}
class Program
{
static void Main()
{
Circle c1 = new Circle(10);
float area = c1.Area();
Console.WriteLine("Area is {0}",area);
Console.ReadLine();
}
}
If we declare PI as an instance field then whenever we create instance of class Circle as c1 then c1 creates copy of PI and radius fields.

When we create another instance of class Circle as c2 then c2 also creates copy of PI and radius fields.

If we declare PI as an static field then c1 and c2 create copy of only radius field. Because PI has been initialized statically so there will be a single copy of PI and any class can refer to that single copy.so, c1 and c2 also refer to the same copy of PI.

If there will be thousands of objects in future then tey will also refer to that single copy of PI.

Hope this helps to clear the concept.

Regards
Sumit Kushwaha
+1
Ramesh Palanivel9y ago
Because static members can only access by class , the objects doesn't have permission to access the variables.
0