  A visual programming language uses pictorial tools such as diagrams to
represent its structural units and control stream. It is useful for enhancing
understanding, maintenance, verification, testing, and parallelism. This paper
proposes a diagrammatic methodology that produces a conceptual representation
of instructions for programming source codes. Without loss of generality in the
potential for using the methodology in a wider range of applications, this
paper focuses on using these diagrams in teaching of C++ programming. C++
programming constructs are represented in the proposed method in order to show
that it can provide a foundation for understanding the behavior of running
programs. Applying the method to actual C++ classes demonstrates that it
improves understanding of the activities in the computer system corresponding
to a C++ program.
