C Standard Library

C <time.h> - difftime() Function

The C <time.h> difftime() function compute difference between two time_t objects as (time_end - time_beg) in seconds. If time_end refers to time point before time_beg, then the function returns negative result.

Syntax

double difftime (time_t time_end, time_t time_beg);

Parameters

`time_beg`	Specify lower bound of the time interval whose length is calculated.
`time_end`	Specify upper bound of the time interval whose length is calculated.

Return Value

Returns (time_end - time_beg) in seconds.

Example:

The example below shows the usage of difftime() function.

#include <stdio.h>
#include <time.h>
 
int main (){
  time_t start, finish;
  long product;

  time(&start);
  for(int i = 0; i < 100000; i++)
    for(int j = 0; j < 25000; j++) 
      product = i*j;

  time(&finish);

  //calculating the time difference
  printf("Time taken = %f seconds",
        difftime(finish, start));   
  return 0;
}

The possible output of the above code could be:

Time taken = 6.000000 seconds

❮ C <time.h> Library