EasyFEM software is an integrated graphics/analysis environment that composes of two main parts, the pre/postprocessors and the solvers. The general structure of the pre- and post-processors consists of several classes that could be classified into four categories, which are the graphics, the finite element, the error handle, and the file I/O handle as shown in Figs. 2 and 3 by the Coad and Yourdon diagram. The implemented data structure model follows the idea given in Ref. with modifications for more convenient coding. The modifications include the use of VB to ease data preparation for both the element-based FE and the edge-based FV solvers.