C Time Functions - C difftime

Returns the difference in seconds between two times.

Prototype

double difftime (time_t end, time_t beginning);

Parameter

This function has the following parameter.

end: Higher bound of the time interval whose length is calculated.
beginning: Lower bound of the time interval whose length is calculated.

If this describes a time point later than end, the result is negative.

Return

The result of (end-beginning) in seconds as a floating-point value of type double.

Example


#include <stdio.h> /* printf */
#include <time.h> /* time_t, struct tm, difftime, time, mktime */
// w  w  w  . j  av a 2s . co  m
int main (){
  time_t now;
  struct tm newyear;
  double seconds;

  time(&now);  /* get current time; same as: now = time(NULL) */

  newyear = *localtime(&now);

  newyear.tm_hour = 0; newyear.tm_min = 0; newyear.tm_sec = 0;
  newyear.tm_mon = 0;  newyear.tm_mday = 1;

  seconds = difftime(now,mktime(&newyear));

  printf ("%.f seconds since new year in the current timezone.\n", seconds);

  return 0;
}

The code above generates the following result.

Example 2


#include <stdio.h>
#include <time.h>
 /* ww  w.  j av a2  s.co  m*/
int main(void){
    time_t now;
    time(&now);
 
    struct tm beg;
    beg = *localtime(&now);
 
    // set beg to the beginning of the month
    beg.tm_hour = 0;
    beg.tm_min = 0;
    beg.tm_sec = 0;
    beg.tm_mday = 1;
 
    double seconds = difftime(now, mktime(&beg));
 
    printf("%.f seconds have passed since the beginning of the month.\n", seconds);
 
    return 0;
}

The code above generates the following result.