1）为了便于区分每辆汽车并了解每辆车当前所处的位置，需要记录汽车的牌照号码和汽车当前的状态。
（2）为了便于停车场的管理，要为每个车位分配一个固定的编号。
（3）当停车场的停车位上都已停满了汽车，又有新的汽车到来时要把它调度到便道上，便道上的车辆要按照进入便道的先后顺序顺次序放在便道上，为便道上的每个位置分配一个固定的编号。当有车从停车位上离开后，便道上的第一辆汽车就立即进入停车位上的某个车位。
（4）当某辆车离开停车场的时候，比他后进停车位的车要为他让路，而且当他开走之后让路的车还要按照原来的停放次序再次进入停车位的某个车位上，为完成这项功能，定义一个结构体。(1) in order to distinguish each car and understand the current location of each vehicle, the number of the car and the current state of the car need to be recorded.

(2) in order to facilitate the management of parking lots, a fixed number should be allocated for each parking space.

(3) when the parking lot parking spaces are full of parked cars, and a new car arrived to dispatch to the sidewalk, sidewalk on the vehicle according to the sequence of sequentially into the sidewalk on the sidewalk, assigned a fixed number for each location on the sidewalk. When a car leaves the parking lot, the first car on the pavement immediately enters a parking space.

(4) when a car from the parking lot, to make way for him than he in the parking car, and when he left the car after the way but also in accordance with the original parking order again into a parking place, for the completion of this function, define a structure.)