设计一个协助停车场计数的程序。该程序有两个按钮：Entering和leaving。汽车进入和离开时单击相应按钮，车辆数量显示在一个标签上。-Design a program to assist the car count. The program has two buttons: Entering and leaving. Cars entered and left click on the appropriate button, on the number of vehicles is displayed in a label.