It has been proved to be effective to solve the real-life problems by means of the principle of diagram. Many phenomena in real world more or less embody some kinds of interrelationship, such as the communication routes between two cities and the networking and operational diagram of one project. The programs of cities or projects are often abstracted to a dot, while the railways routes, the highways routes or two procedures are delineated by linking lines, which forms the so-called diagram.
The following text will lay its emphasis on how to draw up diagrams and models, and on how to use the computer compiler language to design and find a solution.
【Key words】: Diagram, Eluer Circuit, Eluer Diagram.