简单的计算器编程，实现加减乘除基本操作，运算结果为double类型。运行时如果遇到问题，可以把按钮上的图片代码去掉，然后按将button的text改为从1、2、3…8、9、0即可运行成功。-Simple computer program, to achieve the basic operation of addition and subtraction multiplication and division, the result is double type operation. If yo