C++ difftime()

The difftime() function in C++ computes the difference between two times in seconds.

The difftime() function is defined in <ctime> header file.

difftime() prototype

double difftime(time_t end,time_t begin);

The difftime() takes two time_t objects: end and begin, and computes the difference as end - begin and return the result in seconds.

If end refers to the time which occur before begin then the result is negative.


difftime() Parameters

  • end: Represent the end time.
  • begin: Represent the beginning time.

difftime() Return value

  • The difftime() function returns the difference in time between end and begin in seconds.

Example: How difftime() function works

#include <iostream>
#include <ctime>

using namespace std;

int main()
{
	time_t start, finish;
	long product;

	time(&start);
	for(int i=0; i<10000; i++)
	{
		for(int j=0; j<100000; j++)
		{
			product = i*j;
		}
	}
	time(&finish);
	cout << "Time required = " << difftime(finish, start) << " seconds";
	return 0;
}

When you run the program, the output will be:

Time required = 3 seconds

Here, time() function is used to get the current calendar time of type time_t.