C++ time()

#include <iostream>
#include <ctime>
using namespace std;

int main() {

  // use time() with NULL argument
  cout << time(NULL);

  return 0;
}

// Output: 1629799688

time() Syntax

The syntax of the time() function is:

time(time_t* arg);

time() Parameters

The time() function takes the following parameters:

• arg: pointer to a time_t object which (if not NULL) stores the time.

time() Return Value

The time() function returns:

• On Success - the current calendar time as a value of type time_t.
• On Failure - -1 which is casted to type time_t.

time() Prototype

The prototype of time() as defined in the ctime header file is:

time_t time(time_t* arg);

Example 1: C++ time()

#include <iostream>
#include <ctime>
using namespace std;

int main() {
  time_t current_time;

  current_time = time(NULL);

  cout << current_time;
  cout << " seconds has passed since 00:00:00 GMT, Jan 1, 1970";

  return 0;
}

Output

1629810340 seconds has passed since 00:00:00 GMT, Jan 1, 1970

Example 2: C++ time() with Reference Pointer

#include <iostream>
#include <ctime>
using namespace std;

int main() {
  time_t current_time;

  // stores time in current_time
  time(&current_time);

  cout << current_time;
  cout << " seconds has passed since 00:00:00 GMT, Jan 1, 1970";

  return 0;
}

Output

1629810340 seconds has passed since 00:00:00 GMT, Jan 1, 1970