C# String vs StringBuilder

StringBuilder is used to represent a mutable string of characters. Mutable means the string which can be changed. So String objects are immutable but StringBuilder is the mutable string type. It will not create a new modified instance of the current string object but performs modifications on the same StringBuilder object without creating a new object.

The complete functionality of StringBuilder is provided by StringBuilder class which is present in System.Text namespace.

String vs StringBuilder

Example: Demonstrating the differences between String and StringBuilder

Using String Class: Geeks
Using StringBuilder Class: GeeksforGeeks

Explanation:

• Use of concat1 Method: In this method, we are passing a string “Geeks” and performing “s1 = String.Concat(s1, st);” where st is “forGeeks” to be concatenated. The string passed from Main() is not changed, this is due to the fact that String is immutable.
• Use of concat2 Method: In this method, we are passing a string “Geeks” and performing “s2.Append(“forGeeks”)” which modifies the same StringBuilder object by appending new content, as it is mutable.

Converting String to StringBuilder

To convert a String class object to StringBuilder class object, just pass the string object to the StringBuilder class constructor.

Example:

GeeksForGeeks

Converting StringBuilder to String

This conversions can be performed using ToString() method.

Example: