Crossplatform iPhone / Android code sharing

Question

Simply put: What is the most effective way to share / reuse code between iPhone and Android builds?

The two most common scenarios I think would be:

1. Bla

Answer 1

Write as much as possible in plain old C (or C++ if needed) and just include the same files in Android and iPhone. Works on Windows/Mac too. "cross platform" libraries tend to consume you.