IndexOf method returns 0 when it should had return -1 in C# / Java

Question

A friend of mine came to me with this strange behavior which i can\'t explain, any insight view would be appreciated.

Im running VS 2005 (C# 2.0), the following code

Answer 1

0 is correct. Start at position zero and you can (trivially) match a zero-length string. Likewise, "" contains "".