title: How can I calculate Difference from two times in swift 3?
body: <p><a href="https://i.stack.imgur.com/oSWHp.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/oSWHp.png" alt="this is the way I am entering time" /></a></p>
  <p><a href="https://i.stack.imgur.com/btn9T.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/btn9T.png" alt="and I need difference of two times " /></a></p>
  <p>this is the way I am entering time and I need difference of two times</p>