计算两个时刻之间的时间差

[c]代码库

#include <time.h>
#include <stdio.h>
#include <dos.h>
#include <conio.h>

int main ( void )
{
	time_t first, second;

	clrscr();
	first = time ( NULL );  /* Gets system
      time */
	delay ( 2000 );      /* Waits 2 secs */
	second = time ( NULL ); /* Gets system time
      again */

	printf ( "The difference is: %f \
   seconds\n",difftime ( second,first ) );
	getch();

	return 0;
}