title: Finding the time between now and at specific time using swift 3
body: <p>I am trying to find the time (in seconds) between now and a specific time during that day e.g 9:00 AM and if the time now is past this specified time in the day, I would want the time between now and that set time in the next day.</p>
  
  <p>My ultimate goal is to run a function at every hour from 8:00 AM to 5:00 PM, while the application is not open/ in background. If there is a better way to do this without using a timer with an interval of 24 hours then I would really appreciate some suggestions.</p>