How to perform a binary search on IList?

Question

Simple question - given an IList how do you perform a binary search without writing the method yourself and without copying the data to a type with bui

Answer 1

I like the solution with the extension method. However, a bit of warning is in order.

This is effectively Jon Bentley's implementation from his book Programming Pearls and it suffers modestly from a bug with numeric overflow that went undiscovered for 20 years or so. The (upper+lower) can overflow Int32 if you have a large number of items in the IList. A resolution to this is to do the middle calculation a bit differently using a subtraction instead; Middle = Lower + (Upper - Lower) / 2;

Bentley also warned in Programming Pearls that while the binary search algorithm was published in 1946 and the first correct implementation wasn't published until 1962.

http://en.wikipedia.org/wiki/Binary_search#Numerical_difficulties