2、编写一个程序，其功能为：在窗口上放一个按钮，当不断单击按钮时显示它被单击的次数。

3编写一个程序设计一个界面，第一行有3个按钮，第二行中间有一个按钮，第三行有两个按钮。

-2, write a program, its function is: put a button in the window, continue to click the button when it is clicked to display the number. 3 Write a program to design an interface, the first line has three buttons, a button on the middle of the second line, third line has two buttons.