What is Cyclomatic Complexity?

Question

A term that I see every now and then is \"Cyclomatic Complexity\". Here on SO I saw some Questions about \"how to calculate the CC of Language X\" or \"How do I do Y with th

Answer 1

That's sort of it. 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 (command processors, state machines, etc).

Answer 2

Cyclomatric complexity is basically a metric to figure out areas of code that needs more attension for the maintainability. It would be basically an input to the refactoring. It definitely gives an indication of code improvement area in terms of avoiding deep nested loop, conditions etc.

Answer 3

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.

One of the reasons for using metrics like cyclomatic complexity is that in general a human being can only keep track of about 7 (plus or minus 2) pieces of information simultaneously in your brain. Therefore, if your software is overly complex with multiple decision paths, it is unlikely that you will be able to visualize how your software will behave (i.e. it will have a high cyclomatic complexity metric). This would most likely lead to developing erroneous or bug ridden software. More information about this can be found here and also on Wikipedia.

Answer 4

Another interesting point I've heard:

The places in your code with the biggest indents should have the highest CC. These are generally the most important areas to ensure testing coverage because it's expected that they'll be harder to read/maintain. As other answers note, these are also the more difficult regions of code to ensure coverage.

Answer 5

Cyclomatric complexity is a measure of how complex a unit of software is.It measures the number of different paths a program might follow with conditional logic constructs (If ,while,for,switch & cases etc....). If you will like to learn more about calculating it here is a wonderful youtube video you can watch https://www.youtube.com/watch?v=PlCGomvu-NM

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).

Reference: Marsic., I. (2012, September). Software Engineering. Rutgers University. Retrieved from www.ece.rutgers.edu/~marsic/books/SE/book-SE_marsic.pdf

Answer 6

Cyclomatic complexity is computed using the control flow graph. The Number of quantitative measure of linearly independent paths through a program's source code is called as Cyclomatic Complexity ( if/ if else / for / while )