一个简单的swing计算器程序。只涉及加、减、乘、除的运算。运用多种布局管理器和正则表达式。代码风格良好，神奇之处是竟然不超过一百行！非常适合初学者学习。-A simple swing calculator program. Involves only addition, subtraction, multiplication, and division operations. Using a variety of layout managers and regular expressions.