编写一个程序，让一个小球在窗体中跳动，当撞到边缘时，则选择一个角度反弹回去.这是一个很好的程序，希望对大家有帮助-Write a program that allows a small ball in the form of beating, when the hit the edge, you select a point of bounce back. This is a very good program, we want to help