我的思路是：先对年月日进行简单的范围检查，之后将其形成一个tm结构，再调用mktime将该tm转换为一个time_t，在此过程中mktime将对不合法的日期自动进行规范化，如输入为2007-6-31将被转化为2007-7-1。因此比较转换前后的年月日是否相同就能知道日期是否合法。为了便于比较，再调用localtime将time_t转化为tm进行比较。根据比较结果来验证日期是否合法。
引用:bool check_date(int year, int month, int day)
{
if (year < 1900 || month <= 0 || month > 12 || day <= 0 || day > 31)
{
return false;
}
//form time
struct tm tm_new;
tm_new.tm_year = year - 1900;
tm_new.tm_mon = month - 1;
tm_new.tm_mday = day;
tm_new.tm_hour = 0;
tm_new.tm_min = 0;
tm_new.tm_sec = 0;
time_t time_new = mktime(&tm_new);
localtime_r(&time_new, &tm_new);
if (tm_new.tm_year != year - 1900 || tm_new.tm_mon != month - 1 || tm_new.tm_mday != day)
{
return false;
}
else
{
return true;
}
}