画弧函数arc()的应用，同时要注意两个三角函数sin()、cos()（只能用弧度）的使用方法。 -Draw arc function arc () application, at the same time, pay attention to the two trigonometric function sin (), cos () (use only radians) method of use.

简单的计算器代码，支持四则运算和三角函数，阶乘(A calculator that supports four operations and trigonometric functions, factorial)