What’s the difference between System.String and System.StringBuilder classes?

243.

System.String is not immutable

System.StringBuilder is not mutable

System.StringBuilder is mutable

StringBuilder cannot allocate more memory as needed

This class represents a string-like object whose value is a mutable sequence of characters. The value is said to be mutable because it can be modified once it has been created by appending, removing, replacing, or inserting characters.