CRC校验子程序，本程序应用于modebus中的CRC校验，特点对需要校验的串长度没有具体要求，长短皆可-CRC check subroutine, CRC check this procedure is applied in the modebus, there is no specific requirements for the need to check the characteristics of the string length, the length of all

对输入的字符串进行分析，并返回其中最长的单词及其长度-The longest word in the string and its length