一个类似于windows标准计算器的程序 用Java语言编写 可以进行简单的加减乘除 取余 ，平方求导数 ，存储数字 ，调用数字等功能-A similar standard windows calculator program written in Java can be used to check simple addition and subtraction, multiplication and division, the square of the number of derivatio

简单多项式的树结构表示方法，四则运算以及求导运算.-Simple tree structure representation of polynomials, arithmetic and derivative operations.

模仿windows计算器，通过for循环实例化按钮，设置BoxLayout，通过if控制记录被运算数和运算数。通过if控制求导运算、开根号运算、删除键-Mimic the windows calculator for loop to instantiate button, set the BoxLayout operands and operands, if control records. If control of the derivative operator, the square ro

用于计算SPWM 宽度，采用积分求出导通面积然后换算为脉冲数量-SPWM