Programming style: should you return early if a guard condition is not satisfied?

Question

One thing I\'ve sometimes wondered is which is the better style out of the two shown below (if any)? Is it better to return immediately if a guard condition hasn\'t been sat

Answer 1

Having been trained in Jackson Structured Programming in the late '80s, my ingrained philosophy was always "a function should have a single entry-point and a single exit-point"; this meant I wrote code according to Style 2.

In the last few years I have come to realise that code written in this style is often overcomplex and hard to read/maintain, and I have switched to Style 1.

Who says old dogs can't learn new tricks? ;)