time() function in C (original) (raw)

Last Updated : 10 Jan, 2025

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