Code Quality Basics - What Is Code Complexity?


In this article, we find out what code complexity is, and how we keep track of it.

You will learn

  • What Is Code Complexity?
  • What are a few examples of Code Complexity?
  • Why Is Code Complexity important?
  • What are the tools you can use to measure Code Complexity?
  • How can ensure that Code Complexity standards are Adhered to?

Article Series

This is third article in a series of 6 articles on important code quality terminology:

What Is Code Complexity?

Code Complexity is a measure of how difficult your code is to understand.

  • Suppose you have just written a method having 15 if conditions and 3 for loops. How easy do you think it is to understand?
  • Think of a class we have written that has 25 member variables and 75 methods, where some of these methods are huge, having a lot of if conditions and for loops. Is this an easy class to understand?

Measuring Code Complexity

Measuring Cyclomatic And Cognitive Complexity

Cyclomatic complexity is a way of measuring complexity taking into account

  • The number of if else switch conditionals
  • The number of loops - for , while and do while

There is a way to measure the code complexity in SonarQube as well:

image info

You can see that the TreeFactory.java has a cyclomatic complexity measure of 366. That means this class might be a little difficult to understand.

Let’s pick up another file which has a lower complexity listed:

image info

You can see that the findMemberType() method is being highlighted. When you click on it, you get some additional info:

image info

It says that the method has a different complexity measure, the cognitive complexity, that is bad for the code here. It suggests that we refactor this method to correct the complexity.

If you look at this method: image info

It has for loops, if, conditional operator at multiple places, all in interesting combinations!

A complex method is often a sign that the developer has not thought enough about the code.

Understanding Code Complexity

Whenever we write code, we need to keep things small. Simple methods, small classes, small packages, simple components all lead to small and simple applications.

The goal of writing code is not to write large amounts of it, but to achieve a certain functionality. The aim is to achieve that functionality with as little code and complexity as possible.

PMD is also a good static analysis tool to assess code complexity, apart from Sonar.

Addressing Code Complexity

In order to address the problem of complexity, you need to identify it early and monitor it on a regular basis.

You need to include code complexity goals as a major part of your coding standards. These should be regularly tracked.

Do check out our video on the same topic:

image info

Summary

Code complexity is a measure of how difficult it is to understand your code. Generally, large method and classes are code smells. There are different measures for code complexity, and various tools to measure them as well. Keep Refactoring code to reduce complexity.

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