Difference Between Mutable and Immutable in C#

In C#, “mutable” and “immutable” refer to the ability of objects or data to be changed after they are created. Let’s explore the difference between mutable and immutable concepts:

Difference Between Mutable and Immutable in C#

Mutable:

An object or data is considered mutable if its state can be modified after it is created. In other words, mutable objects allow changes to their internal data, properties, or fields. Changes to mutable objects can affect the object’s state and any references to it.

Characteristics of Mutable Objects:

1. Changeable State: Mutable objects can have their internal state altered after they are created. This means that the properties, fields, or data within the object can be modified.
2. Reference Impact: If an object is mutable and you have multiple references to it, changes made through one reference will affect all other references to the same object.
3. Example: Classes in C# are typically mutable. When you modify properties or fields of a class instance, the instance’s state changes.

public class MutablePerson
{
    public string Name { get; set; }
}

MutablePerson person = new MutablePerson();
person.Name = "John"; // Modifying the state of the object

Immutable in C#:

An object or data is considered immutable if its state cannot be modified after it is created. Immutable objects ensure that their values remain constant throughout their lifetime. When you need to “modify” an immutable object, you actually create a new object with the desired changes.

Characteristics of Immutable Objects:

1. Unchangeable State: Immutable objects have a fixed state that cannot be modified once they are created. Any operation that seems like it modifies an immutable object actually creates a new object with the desired changes.
2. Reference Safety: Since immutable objects cannot be changed, multiple references to the same immutable object are safe from unintentional modification.
3. Example: String objects in C# are immutable. When you perform operations that seem to modify a string, you’re actually creating new string objects.

string original = "Hello";
string modified = original + " World"; // Creates a new string with the modified content

Benefits of Immutable Objects:

• Thread Safety: Immutable objects are inherently thread-safe because they can’t be changed once created, avoiding race conditions.
• Simplified Debugging: Immutable objects have consistent states, making debugging and understanding code behavior easier.
• Predictable Behavior: Immutable objects can be safely shared without worrying about unintended changes.

In summary, mutable objects can have their state modified after creation, while immutable objects have a fixed state that cannot be altered. Both concepts have their uses and advantages depending on the context and requirements of your application.