String vs StringBuilderEdit
In C# string is immutable
For example the following create a new string object when you concatenate a value to it
string greeting = "Hello World!";
greeting += " from Tutorials Teacher."; // creates a new string object
StringBuilder is a mutable type. It means you can modify its value without creating a new object each time.
StringBuilder sb = new StringBuilder("Hello World!");
sb.Append("from Tutorials Teacher."); // appends to the same object
The StringBuilder performs faster than the string if you modify a string value multiple times. If you modify a string value more than five times then you should consider using the StringBuilder than a string.