What is cyclomatic complexity?

"Think of cyclomatic complexity as a measure of the number of pathways through a piece of code."  

-Mark Seemann, "Code That Fits in Your Head"

To calculate the cyclomatic complexity of a VBA procedure, start at 1 then add 1 for each of the following statements:

• If
• Else If
• Else
• Case
• For...Next
• For Each...Next
• Do...Loop
• While...Wend
• GoSub...Return
• GoTo

And add 1 for each of these functions:

• IIf
• Nz
• Choose (+1 for each choice)
• Switch (+1 for each expr-value pair)

To write code that "fits in your brain," Seemann recommends limiting cyclomatic complexity to 7.

Cover image created with Microsoft Designer