Difference between string and stringbulder c#

A StringBuilder wears a hardhat, a string doesn't. Seriously though...

A string is deleted and reallocated when you concatenate it, where a StringBuilder isn't. StringBuilders are much more efficient.

BTW, google is free, and this is an easily found answer there.

This article goes a bit more into the details than the note posted at dotnetuncle
String Vs StringBuilder (C#)[^]

It might help you,

StringBuilder vs. String / Fast String Operations with .NET 2.0[^]

:)

StringBuilder is a mutable class, meaning you can insert/append/replace/etc. without creating a new StringBuilder each time.
String is immutable, each time you perform an operation that "changes" it you are creating a new string to replace the old one.
As mentioned above multiple times, that makes the StringBuilder more efficient for operations that manipulate strings.

Please see the below articles for more and deep understanding:

http://www.dotnetuncle.com/difference/41_string_stringbuilder.aspx[^]

http://www.dotnetfunda.com/forums/show/8441/what-is-the-difference-between-string-and-stringbuilder-in-csharp-with[^]

http://www.c-sharpcorner.com/blogs/3778/difference-between-stringbuilder-and-string.aspx[^]

http://msdn.microsoft.com/en-us/library/2839d5h5(v=vs.110).aspx[^]

Please take a look here,
http://stackoverflow.com/questions/3069416/difference-between-string-and-stringbuilder-in-c-sharp

String:
Its a class used to handle strings. String object is used to concatenate two strings. Strings are immutable.Slower

String Builder:

This is also the class used to handle strings.Here Append method is used. String Builder is mutable.Faster [spam link removed]