Definition of Cyclomatic Complexity

•Project management is often unaware of the impact of software processes. In the above case, if the project management were to be aware of the nature of the change approval process and its impact on the schedule, they could have taken appropriate steps to avoid incurring technical debt. For instance, they could have optimized the change approval process so that the schedule is met. Alternately, they could have modified the schedule to ensure that the team in Country B feels encouraged to follow good design practices and the change approval process set in place. Being new to the project, she was puzzled about why this class was so huge and why no refactoring had been performed on it so far.

• I have no doubt that you could conceive of a method with a high cyclomatic complexity score that’s also relatively easy to understand, test, and maintain.
• Consider the control flow graph of your function, with an additional edge running from the exit to the entrance.
• You can sort by highest complexity and drill down into individual functions.
• Of course, you can still have terrible code with low complexity, or decent code with high complexity.
• The cyclomatic number of the graph is defined as the dimension of this space.
• For instance, refactoring the class with lines would require breaking it up into several smaller cohesive classes.

For the most part, complexity under 6 to 8 is probably fine as long as the code itself is well formatted. Anything from 8-15 is questionable, and anything over 15 is probably not great. Anything over 25 is almost certainly a problem unless proven otherwise.

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The decision points may be your conditional statements like if, if … else, switch , for loop, while loop etc. Boolean operators can add either one or nothing to complexity. For instance, one may be added if a Boolean operator is found within a conditional statement. The metric is completely independent of the code style. This is a big difference to the common line of code metric.

Determining the independent path executions thus proven to be very helpful for Developers and Testers. For example, consider a program that consists of two sequential if-then-else statements. Is an upper bound for the number of test cases that are necessary to achieve a complete branch coverage. “relative” means the path must begin and end at an entry or exit point. By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. Making statements based on opinion; back them up with references or personal experience.

How to Calculate Cyclomatic Complexity

This makes the cyclomatic complexity of the function reach 3. I’ll use a single function as an example, progressively increasing its complexity as we go. The examples will be in C# for the simple reason that it’s my go-to language.

As the program grows in this fashion, it quickly reaches the point where testing all of the paths becomes impractical. This corresponds to the characterization of cyclomatic complexity as “number of loops plus number of components”. This corresponds to the intuitive notion of cyclomatic complexity, and can be calculated as above. You can probably intuitively see why the linked graph has a cyclomatic complexity of 3. Cyclomatric complexity is basically a metric to figure out areas of code that needs more attension for the maintainability. It definitely gives an indication of code improvement area in terms of avoiding deep nested loop, conditions etc.

The Why of Cyclomatic Complexity

Time Complexity where loop variable is incremented by 1, 2, 3, 4 .. In the case of simple comparisons and decision structures, it may give a misleading figure. It is used to measure the minimum effort and best areas of https://www.globalcloudteam.com/ concentration for testing. Connect and share knowledge within a single location that is structured and easy to search. However, when you consider the side effect of the Boolean operator, there are actually two decisions.

The cyclomatic complexity of a method also denotes the number of unit test cases required to achieve the 100% code coverage for that method. Computing the cyclomatic complexity on some samples allows us to better identify how source code affects the metric. Developers will resist creating unit tests with the goal of code coverage. In their previous positions, they have always been rewarded for producing new functionality or squashing bugs. In most cases, never before has a measurable metric of quality been introduced into their goals and they have not been financially rewarded for producing quality.

What’s the Big Deal?  Who Cares About Cyclomatic Complexity?

Use it as a means for evaluating your code and communicating its properties to outsiders. Because if you don’t, sooner or later at wave of management or consultants will. Where the idea of cyclomatic complexity really shines is in aggregate. Are you going to have methods with a high complexity score that aren’t really so bad? Likewise, will you have awful methods with a low cyclomatic complexity score? But if you pull away from individual methods and start evaluating your codebase as a whole, average cyclomatic complexity becomes both more accurate and more telling.

As complexity has calculated as 3, three test cases are necessary to the complete path coverage for the above example. PCMag.com is a leading authority on technology, delivering lab-based, independent reviews of the latest products and services. Our expert industry analysis and practical solutions help you make better buying decisions and get more from technology. As you saw in the last section, for the simple cases, calculating the cyclomatic complexity isn’t needed because you can literally see it. To drive the point home, I’ll walk you through an example of cyclomatic complexity in practice.

The Basics of Cyclomatic Complexity and Why Every Programmer Should Know About It

But, in cases where callers pass zero for y, the method will execute along a different path, returning zero after the if condition evaluates to true. Test-driven development is one way to bring in unit tests for the purposes of code coverage. To show the value that this work has to the larger organization, it may be necessary to set aside specific time during the work week what is cyclomatic complexity to have them gather and be trained how to do TDD. Without actually setting aside time to introduce this new concept, the old saying of you get what you pay for is very true and results will be spotty at best. A few developers may pick up on the concepts and begin performing them in their daily work, but more commonly the whole idea will fizzle like a wet firecracker.

More information about this can be found here and also on Wikipedia. The answers provided so far do not mention the correlation of software quality to cyclomatic complexity. Research has shown that having a lower cyclomatic complexity metric should help develop software that is of higher quality. It can help with software quality attributes of readability, maintainability, and portability. In general one should attempt to obtain a cyclomatic complexity metric of between 5-10. After all,any metric is inherently reductionist, and many metrics exist in spite of methodological disagreements.

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I mean, complexity makes sense, but what does “cyclomatic” mean, exactly? Well, “cyclomatic number” serves as an alias for something more commonly called circuit rank. Circuit rank measures the number of independent cycles within a cyclic graph. So I suppose he coined the neologism “cyclomatic complexity” by borrowing a relatively obscure discrete math concept for path independence and applying it to code complexity.