Fields are variables declared directly in a class or struct. They store the data or state of an objects (instance fields) or the class itself (static fields).

** Types of Fields** 1. Instance field 2. Static field 3. Readonly field

1. Instance field

Instance fields are associated with an instance of a class. Each object created from the class has its own copy of the instance fields.

class Person
{
	public string Name; // Instance field
	public int Age; // Instance field
}

When to use instance fields?

• Object-specific data: When you want to store data that is specific to each instance of a class, such as a person's name or age.

2. Static field

Shared across all instances of a class, static fields belong to the class itself rather than any particular object. They are accessed using the class name.

class MathConstants
{
	public static double Pi = 3.14159; // Static field
}

When to use static fields?

• Shared data: When you want to store data that is common to all instances of a class, such as mathematical constants or configuration settings.

3. Readonly field

Can be set only in declaration or constructor, and cannot be modified afterward. This makes them ideal for values that should remain constant after initialization.

class Circle
{
	public readonly double Radius; // Readonly field
	public Circle(double radius)
	{
		Radius = radius; // Assigning value in constructor
	}
}

When to use readonly fields?

• Immutable after creation: When you want to ensure that a field's value cannot be changed after it has been initialized, such as the radius of a circle or a person's birthdate.