Function prototype to read character from string.

You can find more information in comments below.

/*
    Get character from string function prototype 
    @param s String to get character from 
    @param min Minimum allowed position to look at 
    @param max Maximum allowed position to look at 
    @param index Symbol index to retreive 
    @return Symbol at specified position(could be transformed to upper or lower case) or 0x00 
    */
    using FGetChar = wchar_t(*)(const String &s, const int min, const int max, const int index);