String Builder and String

String Builder and String :

Mutable: can Change

Immutable: cannot change

A string instance is immutable. You cannot change it after it was created. Any operation that appears to change the string instead returns a new instance:

Objects of type StringBuilder are mutable where as objects of type System.String  are immutable.

As StringBuilder objects are mutable, they offer better performance than string objects of type System.String.

StringBuilder class is present in System.Text namespace where String class is present in System namespace.