Introduction - If you have any usage issues, please Google them yourself
Define a segment class a rectangular base class, the base class has a beginning and end coordinates, there is a member function of the angle between the output of the left and the length and the line segment and the x axis. The moment two coordinates of a line segment object as a section of its own position, it has also an edge, can output the rectangular coordinates of the vertices of the four. Given in the class definition, and application to verify their function.