Using Kolmogorov Complexity to Study the Coevolution of Header Files and Source Files of C-alike Programs

In C-alike programs, the source code is separated into header files and source files. During the software evolution process, both these two kinds of files need to adapt to changing requirement and changing environment. This paper studies the coevolution of header files and source files of C-alike programs. Using normalized compression distance that is derived from Kolmogorov complexity, we measure the header file difference and source file difference between versions of an evolving software product. Header files distance and source files distance are compared to understand their difference in pace of evolution. Mantel tests are performed to investigate the correlation of header file evolution and source file evolution. The study is performed on the source code of Apache HTTP web server.