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. The Javadocs point out that indexOf works as follows:

The integer returned is the smallest value k such that:

 this.startsWith(str, k)

Any string starting with "" is equal to the original string (and every string starts with ""), so the smallest k for str = "" is always 0.