获取系统时间

#include <iostream>
#include<ctime>

using namespace std;

int main()
{
time_t tt = time(NULL);
tm* t = localtime(&tt);
printf("%d-%02d-%02d %02d:%02d:%02d\n",
t->tm_year + 1900,
t->tm_mon + 1,
t->tm_mday,
t->tm_hour,
t->tm_min,
t->tm_sec);

/*
//基于当前系统的当前日期/时间
time_t now = time(0);

//把now转换成字符串格式
char * dt = ctime(&now);
cout << "当前时间："<< dt << endl;

//把now转换成tm结构
tm *gmtm = gmtime(&now);
dt = asctime(gmtm);
cout << "UCT 日期和时间：" << dt << endl;
*/
/*
// 基于当前系统的当前日期/时间
time_t now = time(0);

tm *ltm = localtime(&now);

// 输出 tm 结构的各个组成部分
cout << 1900 + ltm->tm_year ;
cout << 1 + ltm->tm_mon ;
cout << ltm->tm_mday << endl;
cout << ltm->tm_hour << ":";
cout << ltm->tm_min << ":";
cout << ltm->tm_sec << endl;

*/

return 0;
}