1、实现十进制下的四则运算（加、减、乘、除）和四则混合运算

2、实现十进制转化为二进制或十六进制

3、实现进行一些常用的函数运算（比如sin、cos、tan、cot、sqrt、ln等）

4、实现“（”，“）”符号的表达式的计算-1 decimal, under the four operations ( addition, subtraction, multiplication, addition) and four mixed computing

2, decimal converted to binary or hexadecimal sixteen

3, implementation of some commonly used function operation ( such as sin, cos, Tan, cot, sqrt, LN etc.)

4, achieve" ("," )" symbolic expressions for the calculation