Cyclomatic complexity metrics are an important aspect of determining the quality of software. They provide insight into the overall code complexity of functions or software components by quantifying the number of linearly independent paths or decision logic. Cyclomatic complexity metrics are an important indicator of your source code’s readability, maintainability, and portability. Cyclomatic complexity is a software metric used to measure the complexity of a program. Thomas J. McCabe developed this metric in 1976.McCabe interprets a computer program as a set of a strongly connected directed graph.
Checking and analyzing the complexity of the code with the help of Visual Studio is a reasonably straightforward task. Code from Figure 3 will generate the complexity of one, which can be seen in the image above. But according to the formula from Figure 2 should be a complexity of 2.
The Why of Cyclomatic Complexity
Based on complexity number, team can conclude on the actions that need to be taken for measure. It is important in designing test cases because it reveals the different paths or scenarios a program can take . “To have good testability and maintainability, McCabe recommends that no program module should exceed a cyclomatic complexity of 10″(Marsic,2012, p. 232). One of the reasons for using metrics like cyclomatic complexity is that in general a human being can only keep track of about 7 pieces of information simultaneously in your brain.
Learn more about checking and analyzing the complexity of code with C# and Visual Studio. Based on the Cyclomatic complexity the project released can be shipped and the product can be on board in the organization. If the code is reformatted it does not affect the https://www.globalcloudteam.com/ Cyclomatic complexity. If the value of V is equal to 1 then there is only one path in the graph which means there is only one solution to the computer program. When it makes sense, leverage third-party code in the forms of open-source libraries and frameworks.
How this metric is useful for software testing?
It was about 2000 lines of if statements in one method. Basically unmaintainable, untestable, full of potential bugs. Imagine all the unit test cases needed for that branching logic! Drilling down into class and method level complexity will determine areas of the code that need to be refactored into https://www.globalcloudteam.com/glossary/cyclomatic-complexity/ smaller methods or redesigned to elminate the complexity. An application with few lines of code and a high number of conditionals nested within loops could have an extremely high cyclomatic complexity. On the other hand, an application with few conditions might have a low cyclomatic complexity.
“relative” means the path must begin and end at an entry or exit point. 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 concentration for testing.
What exactly is cyclomatic complexity?
The higher the cognitive complexity, the harder it is to read and maintain the existing code base. As you’ll soon see, cyclomatic complexity is easy to understand and calculate. This is great since it has important implications for code maintainability and testing. Cyclomatic complexity is especially important when it comes to testing.
A good starting point might be the Wikipedia article on cyclomatic complexity. It has a couple of snippits of pseudocode and some graphs that show what cyclomatic complexity is all about. If you want to know more, you could also read McCabe’s paper where he defined cyclomatic complexity. Often, code review can take cyclomatic complexity into account, even flagging problematic functions that may need manual review.
Tools used for Calculating Cyclomatic Complexity
Since refactoring was not taken up at regular intervals, even during the maintenance phase, the existing classes continued to bloat and became increasingly bug-prone. One of the participants at the Smells Forum shared her experience that highlighted how the viscosity of the environment can lead to the introduction of Insufficient Modularization smell. She had just joined a globally distributed software development project concerning a critical clinical workflow product. The ownership of the code base was with the central team located in Country A, and she was a part of the offshore development team located in Country B. Cyclomatic complexity is not a perfect metric nor a fool-proof method for increasing code quality.
E is the number of edges of the graph, N is the number of nodes and M is McCabe’s complexity. What I have personally read a lot of times is that methods with a CC higher than 10 have higher risks of defects. As complexity has calculated as 3, three test cases are necessary to the complete path coverage for the above example. It’s a very basic metric and looks over the nuance of the code itself.
Cyclomatic Complexity
Some of the tactics we’ve just seen can contribute to reducing the number of if statements in your code. For instance, instead of using flag arguments and then using an if statement to check, you can use the decorator pattern. I recommend you to use the tool called Lizard and you can find the resource code and download the zip file at github. It also has a online version if there is not much confidential information in your code.
- Detection tools might require the definition of several parameters.
- So, for instance, addition of one arc increases the complexity value by one for both small and large flowgraphs.
- We now have yet another branching that verifies the length of the person’s name.
- For starters, bear in mind that you don’t actually need to calculate it.
- Learn the formula to calculate cyclomatic complexity with examples.
- The notion of program graph has been used for this measure, and it is used to measure and control the number of paths through a program.
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. However, each branch of a “case” or “switch” statement tends to count as 1. In effect, this means CC hates case statements, and any code that requires them .
Properties
However, higher complexity could be a sign of a potentially larger problem. Cyclomatic complexity is easy to apply a metric rule that could be integrated as an additional validation rule when developing. With that approach, we cleaned the code a bit and improved the readability and maintainability. The example from Figure 6 has an additional decision code, which increased complexity by +1. N represents the total number of nodes in the flow graph.
