pmccabe calculates McCabe-style cyclomatic complexity for C and C++
source code. Per-function complexity may be used for spotting likely
trouble spots and for estimating testing effort.

pmccabe also includes a non-commented line counter, decomment which
only removes comments from source code; codechanges, a program to
calculate the amount of change which has occurred between two source
trees or files; and vifn, to invoke vi given a function name rather
than a file name.

WWW: http://www.parisc-linux.org/~bame/pmccabe/