Difference between string class & stringbuilder class in c#

String

StringBuilder

String is immutable, meaning that once you created string object then you can't modify it

StringBuilder is mutable, meaning that once you created string builder object then you can modify or append without creating a new instance for every time

Any operation that appears to change the string, it creates a new instance of string type in memory

Any operation that appears to modify or append new string, it doesn't create a new instance of string type in memory

Required Class is System.String

Required Class is System.Text.StringBuilder

Required Namespace is System

Required Namespace is System.Text

String is slower as compare to string builder object when we deals with large size of strings

StringBuilder is faster as compare to string object when we deals with large size of strings

String is efficient when we deals with static or smaller size of string means we don't need to modify later on

StringBuilder is efficient when we deals with dynamic or larger size of string means we want to modify that string later on