设计一个基于Swing的简单计算器，用于整数的加减乘除运算。1.上方为文本框，位于所属容器的北部(BorderLayout.North),下方为数字按钮和运算符按钮，放在一个JPanel中，采用网格布局，该Panel位于所属容器的南部(BorderLayout.South)。

2.在文本框中输入两个数据，按加/减/乘/除 按钮就进行这两个数的相应运算，并将结果输出到文本框中 (可通过ActionEvent事件处理程序完成)。

3.按钮C是用来对文本框中的内容清零的。

-Design a simple Swing-based calculator for integer arithmetic operations. 1. The top of the text box, the north (BorderLayout.North) belongs container located below the operator for the number buttons and buttons in a JPanel, using a grid layout, located in the south belongs to the Panel container (BorderLayout.South) .

2 Enter both data in the text box, press the add/subtract/multiply/divide button to perform the corresponding operation of these two numbers, and outputs the results to a text box (to be completed by ActionEvent event handler).

3 C button is used for the contents of the text box is cleared.