#include <iostream>
#include <ctime>
using namespace std;
int main(void)
{
struct tm *times; //定义时间指针变量.....(只能用指针)
time_t t; //定义系统时间变量,供提供系统时间
t = time(0); //当前系统时间给变量t
times = localtime(&t); //把系统时间变量强制转换成tm结构体形式时间
cout << times->tm_hour; //显示时间
cout << times->tm_min;
cout << times->tm_sec;
return 0;
}

-----------------------------------time头文件中的tm结构体.......
struct tm
{
int tm_sec; /* Seconds: 0-59 (K&R says 0-61?) */
int tm_min; /* Minutes: 0-59 */
int tm_hour; /* Hours since midnight: 0-23 */
int tm_mday; /* Day of the month: 1-31 */
int tm_mon; /* Months *since* january: 0-11 */
int tm_year; /* Years since 1900 */
int tm_wday; /* Days since Sunday (0-6) */
int tm_yday; /* Days since Jan. 1: 0-365 */
int tm_isdst; /* +1 Daylight Savings Time, 0 No DST,
* -1 don't know */
};