Page 190 - DCAP305_PRINCIPLES_OF_SOFTWARE_ENGINEERING

Principles of Software Engineering

Notes as 10 is a common limit for cyclomatic complexity, 60 is a common limit for the number of lines
of code, the somewhat archaic rationale being that each software module should fit on one
printed page to be manageable. Although the number of lines of code is often used as a crude
complexity measure, there is no consistent relationship between the two. Many modules with
no branching of control flow (and hence the minimum cyclomatic complexity of one) consist
of far greater than 60 lines of code, and many modules with complexity greater than ten have
far fewer than 60 lines of code. For example, Figure 9.4 has complexity 1 and 282 lines of code,
while Figure 9.5 has complexity 28 and 30 lines of code. Thus, although the number of lines of
code is an important size measure, it is independent of complexity and should not be used for
the same purposes.
Several flow graphs and their complexity

Several actual control flow graphs and their complexity measures are presented in through,
to solidify understanding of the measure. The graphs are presented in order of increasing
complexity, in order to emphasize the relationship between the complexity numbers and an
intuitive notion of the complexity of the graphs. (See Figure 9.6 and Figure 9.7)

Figure 9.4: Control Flow Graph with Complexity 1

184 LOVELY PROFESSIONAL UNIVERSITY