IRiSS (Information Retrieval based Software Search) is a software exploration tool that uses an indexing engine based on an information retrieval method. IRiSS is implemented as an add-in to the Visual Studio .NET development environment and it allows the user to search a C++ project for the implementation of concepts formulated as natural language queries. The results of the query are presented as ranked list of software methods or classes, ordered by the similarity to the user query. A second component of IRiSS provides another searching method based on regular expression matching. This method is based on the existing “find” feature form the Visual Studio environment and it has an improved format for the display of the search results.