# difftime() function in C++

In this article we are going to discuss the difftime() function in C++, its syntax, working and its return values.

difftime() function is an inbuilt function in C++ which is defined in header file. The function accepts two parameters of time_t type, function calculate the difference between the two times

## Syntax

double difftime(time_t end, time_t beginning);

## Return value

Returns the difference of the time in seconds, stored as double data type.

## Example

Live Demo

#include <stdio.h>
#include <time.h>
int main () {
time_t now;
struct tm newyear;
double seconds;
time(&now); /* get current time; */
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;
}

## Output

If we run the above code it will generate the following output −

3351041 seconds since new year in the current timezone.

## Example

#include <iostream>
#include <ctime>
using namespace std;
int main() {
time_t start, ending;
time(&start);
for (int i = 0;
i < 50000; i++) {
for (int j = 0; j < 50000; j++);
}
for (int i = 0; i < 50000; i++) {
for (int j = 0; j < 50000; j++);
} for (int i = 0; i < 50000; i++) {
for (int j = 0; j < 50000; j++);
} time(&ending);
cout << "Total time required = " << difftime(ending, start) << " seconds " << endl;
return 0;
}

## Output

If we run the above code it will generate the following output −

Total time required = 37 seconds