Complexity Simplified: How to identify and manage cyclomatic complexity

Introduction

How can you tell when code has become too complex??Symptoms often include code that has become difficult to maintain or extend. But complex code is something that can be objectively measured and simplified, while retaining all of the functionality of the original code.?This article provides a clear and straightforward introduction to the metric of cyclometic complexity and how it can be used to identify and simplify complex code.

Definition

Cyclomatic complexity is a metric used to determine the complexity of a method, based on the number of decision points in that method. The if statement is the most common implementation of a decision point.

Examples

Here's a basic example of a method with cyclomatic complexity metric of 1 because it has a single decision point represented by a single if statement:

function MyMethod(x){?? 
    if(x == 0){?????? 
        // do something?? 
    }
}        

Here's a basic example of a method with cyclomatic complexity metric of 2 because it has 2 decision points represented by 2 if statements:

function MyMethod(x){?? 
    if(x == 0){?????? 
        // do something?? }
    else if(x == 1){
?????? // do something else?? 
    }
}        

Thresholds

As methods grow in complexity, they become less maintainable and less extendable. This impacts code quality and introduces risk. As a result, Developers will often tend to avoid these methods in a codebase.

A cyclomatic complexity metric of 5 or less is generally considered attainable for most methods, and a method with a cyclomatic complexity metric over 10 is generally considered too complex. Some enterprise codebases may occassionally even have unruly methods with a cyclomatic complexity metric of 50-100 or more! Those methods are red flags ??and present excellent candidates for refactoring.

Refactoring

At the most basic level, these methods can be broken up into smaller more specialized methods to reduce complexity. With proper abstraction, all of the original logic can be retained, with much higher code quality in regards to maintainability, extendability and reliability.

Assessment

Code quality tools exists for most programming languages that can measure and enforce thresholds for code complexity, including cyclomatic complexity. These tools are widely used in modern development workflows to ensure maintainability and reduce technical debt. ChatGPT or a similar AI can also be used to identify the cyclomatic complexity for methods in a code file.

Next Steps

Curious about how to further optimize your codebase for cyclomatic complexity? Want to ensure that your software is scalable and easy to maintain? Then feel free to reach out to info@adac1001.com for a free consultation!

Additional Reading

Code Complete: A Practical Handbook of Software Construction, Second Edition by Steve McConnel

Clean Code: A Handbook of Agile Software Craftsmanship by Robert C. Martin

Refactoring: Improving the Design of Existing Code by Martin Fowler