利用KMP算法，忽略大小写的字符串匹配 查找子字串在父字串的位置-Use of KMP algorithm, case-insensitive substring string matching to find the location of the parent string

我们经常需要在一串数字（有正负）查找和最大的子数字串，该程序基于C语言实现-We often need to find the maximum and sub-numeric string in a string of numbers (positive and negative), the program is based on the C language