一组转换函数用于十六进制字符串二进制字符串八进制字符串到十进制整数相互转换，对数值运算和运算转换有帮助-a group function for converting hexadecimal string octal binary string string to decimal integer conversion of numerical computing and Operational Conversion help

利用牛顿法实现迭代运算。计算方法为数值计算书上提到的流程-Achieved using Newton iteration method. Process for the numerical calculation method mentioned in the book

高精度阶乘运算，可以计算到很大的值，弥补了使用int型变量带来的数值限制-Precision factorial operation can be calculated to a large value, to make up for the numerical limit the use of int type variables to bring the