设计一个简单计算器，如下图所示。在“操作数”标签右侧的两个文本框输入操作数，当单击操作符＋，－，×，÷按钮时，对两个操作数进行运算并将结果填入到“结果”标签右侧的文本框中。-Design a simple calculator, as shown below. In the " operand"　tab on the right of the text box to enter two operands, operators+,-,×,÷ when you click the button, the operation of the two operands and the results fill in the " Results"　tab Right side of the text box.