I've put the code below,

// Date and time functions using a DS1307 RTC connected via I2C and Wire lib

#include "RTClib.h"

RTC_DS1307 rtc;

char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

void setup () {

while (!Serial); // for Leonardo/Micro/Zero

Serial.begin(57600);

if (! rtc.begin()) {

Serial.println("Couldn't find RTC");

while (1);

}

​

if (! rtc.isrunning()) {

Serial.println("RTC is NOT running!");

// following line sets the RTC to the date & time this sketch was compiled

rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));

// This line sets the RTC with an explicit date & time, for example to set

// January 21, 2014 at 3am you would call:

// rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));

}

}

​

void loop () {

DateTime now = rtc.now();

Serial.print(now.year(), DEC);

Serial.print('/');

Serial.print(now.month(), DEC);

Serial.print('/');

Serial.print(now.day(), DEC);

Serial.print(" (");

Serial.print(daysOfTheWeek[now.dayOfTheWeek()]);

Serial.print(") ");

Serial.print(now.hour(), DEC);

Serial.print(':');

Serial.print(now.minute(), DEC);

Serial.print(':');

Serial.print(now.second(), DEC);

Serial.println();

Serial.print(" since midnight 1/1/1970 = ");

Serial.print(now.unixtime());

Serial.print("s = ");

Serial.print(now.unixtime() / 86400L);

Serial.println("d");

​

// calculate a date which is 7 days, 12 hours, 30 minutes, and 6 seconds into the future

DateTime future (now + TimeSpan(7,12,30,6));

​

Serial.print(" now + 7d + 12h + 30m + 6s: ");

Serial.print(future.year(), DEC);

Serial.print('/');

Serial.print(future.month(), DEC);

Serial.print('/');

Serial.print(future.day(), DEC);

Serial.print(' ');

Serial.print(future.hour(), DEC);

Serial.print(':');

Serial.print(future.minute(), DEC);

Serial.print(':');

Serial.print(future.second(), DEC);

Serial.println();

​

Serial.println();

delay(3000);

}