Structural Complexity

Structural Complexity relates to the complexity of the code in terms of size, control flow, the number of fields and methods (per class), etc.

It provides a way to judge how complex software is to test and maintain.

Structural software complexity (5:33)

Wikipedia pages on:

Home page of the "lizard" tool to measure complexity in source code.

What kind of metric measurement tool is typically available on any command line?
What kinds of features do you associate with complex code?
What kinds of software metrics have you heard of or used before?