说明：  模拟某校五层教学楼的电梯系统。该楼有一个自动电梯，能在每层停留。五个楼层由下至上依次称为地下层、第一层、第二层、第三层和第四层，其中第一层是大楼的进出层，即是电梯的“本垒层”，电梯“空闲”时，将来该层候命。五个楼层从下到上的编号为：0、1、2、3、4。除了地下层外，每一层都有一个要求向下的按钮除了第四层外，每一层都有一个要求向上的按钮。对应的变量为：CallUp[0..3]和CallDown[1..4]。电梯内的五个目标层按钮对应的变量为：CallCar[0..4]。
(With the rapid development of modern society, the more and more buildings are built, the elevator has become an indispensable tool for people's life. Therefore, it is meaningful to understand the elevator's operation system. This paper simulates the operation of the elevator in the environment of c++,and has a certain understanding of the operation of the elevator.)