time() function in C

The time() function is defined in time.h (ctime in C++) header file. This function returns the time since 00:00:00 UTC, January 1, 1970 (Unix timestamp) in seconds. If second is not a null pointer, the returned value is also stored in the object pointed to by second.

Syntax:

time_t time( time_t *second )

Parameter: This function accepts single parameter second. This parameter is used to set the time_t object which store the time.
Return Value: This function returns current calendar time as a object of type time_t.

Time Complexity: O(1)

Auxiliary Space: O(1)

Program 1:

C

// C program to demonstrate
// example of time() function.
#include <stdio.h>
#include <time.h>

int main ()
{
    time_t seconds;

    seconds = time(NULL);
    printf("Seconds since January 1, 1970 = %ld\n", seconds);

    return(0);
}

Output:

Seconds since January 1, 1970 = 1538123990

Example 2:

C

// C program to demonstrate
// example of time() function.

#include <stdio.h>
#include <time.h>

int main()
{
    time_t seconds;

     // Stores time seconds
    time(&seconds);
    printf("Seconds since January 1, 1970 = %ld\n", seconds);

    return 0;
}

Output:

Seconds since January 1, 1970 = 1538123990