Split const char* in C++

Question

How could I split const char*?

I have a date pattern saved on a const char. I would like to know if it is valid or not. Since I can't split const char*, what should I do then?

Answer 1

You can easily use sscanf() , or perhaps strptime() if your system has it, to parse the day/month/year fields from a character buffer. You can also put the text into a std::stringstream then stream the values into numeric variables, ala:

std::istringstream is("2010/11/26");
int year, month, day;
char c1, c2;
if (is >> year >> c1 >> month >> c2 >> day &&
    c1 == '/' && c2 == '/')
{
    // numeric date fields in year, month, day...
    // sanity checks: e.g. is it really a valid date?
    struct tm tm;
    tm.tm_sec = tm.tm_min = tm.tm_hour = tm.tm_wday = tm.tm_yday = tm.tm_isdst = 0;
    tm.tm_mday = day;
    tm.tm_mon = month;
    tm.tm_year = year;
    time_t t = mktime(&tm);
    struct tm* p_tm = localtime(&t);
    if (p_tm->tm_mday == day && p->tm_mon == month && p->tm_year == year)
        // survived to/from time_t, must be valid (and in range)
        do something with the date...
    else
        handle date-like form but invalid numbers...
}
else
    handle invalid parsing error...

You should try them out and post specific questions if you have difficulties.

Answer 2

You should add details to your question, now it's overly broad. In general, you can use boost::regex_match to determine whether a given regular expression matches all of a given character sequence.