Why is the code in most STL implementations so convoluted?

Question

The STL is a critical piece of the C++ world, most implementations derive from the initial efforts by Stepanov and Musser.

My question is given the criticality of the co

Answer 1

To add on what people have said already, the style you see is the GNU style. Ugly? Perhaps, that's in the eye of the beholder. But it's a strictly-defined style, and it does make all code look similar, as opposed to resistant to getting used to.