输入A、B两点坐标，计算B与A之间的方位角，坐标系为直角坐标系，如输入（0,0）和（1,1），则方位角为45度-Enter the coordinates of A and B and calculate the azimuth angle between B and A. The coordinate system is Cartesian coordinate system, such as input (0,0) and (1,1), the azimuth angle is 45 deg