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在 C++ 中拆分 const char*

发布于 2024-10-16 08:17:37 字数 95 浏览 3 评论 0原文

我如何拆分 const char* ？

我有一个日期模式保存在 const 字符上。我想知道它是否有效。既然我不能拆分const char*，那我该怎么办呢？

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嘦怹 2024-10-23 08:17:37

您可以轻松地使用 sscanf() 或 strptime()（如果您的系统有）来解析字符缓冲区中的日/月/年字段。您还可以将文本放入 std::stringstream 中，然后将值流式传输到数字变量中，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...

您应该尝试一下，如果遇到困难，请发布具体问题。

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.

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