Abstract: Developers or maintainers are finging it harder to understand and maintain software. Given a system under maintenance, developers may use a code search technique to locate the code of their interests. However, it may be difficult for them to understand the elements and the relation among them for the system at hand. Thus, the returned code may not fit their needs. It is thus necessary to have a word base to recover the elements and their relations for a target system. A tool, WB4HPR(word base for historical program repository) was introduced which focuses on building the word base for a specific system. WB4HPR can retrieve the words, recover the relationship between them, and display the evolution of these words during the program evolution to help developers and maintainers comprehend the program, while effectively keeping the consistency of the use of words during the software maintenance process.

Key words: source code analysis, word base, program comprehension