C語言下如何獲得當前時間，並顯示出來 然後比較兩個時間的大小

#include <conio.h>

#include <time.h>

#include <dos.h>

void main()

{

time_t t1,t2;

struct tm *tm;

t1=time(NULL);

tm=localtime(&t1);

printf("%04d-%02d-%02d %02d:%02d:%02d\n",tm->tm_year+1900,

tm->tm_mon+1,tm->tm_mday,tm->tm_hour,tm->tm_min,tm->tm_sec);

sleep(10);

t2=time(NULL);

tm=localtime(&t2);

printf("%04d-%02d-%02d %02d:%02d:%02d\n",tm->tm_year+1900,

tm->tm_mon+1,tm->tm_mday,tm->tm_hour,tm->tm_min,tm->tm_sec);

printf("%d\n",t2-t1);

getch();

}