title: Binary operator '>' cannot be applied to two 'Int?' operands
body: <p>I've just started with Swift and am learning the basics. I've been playing around with Playgrounds and have come across an error whilst testing some code.</p>
  
  <pre><code> //creating a Struct for humans
  struct Human {
      var firstName: String? = nil
      var surName: String? = nil
      var age: Int? = nil
      var height: Int? = nil
  }
  
  var personA = Human()
  personA.firstName = "Jake"
  personA.surName = "-"
  personA.age = 26
  personA.height = 185
  
  print (personA)
  
  if (personA.age == 30) {
      print("You're 30 years old")
  } else {
      print("You're not 30")
  }
  
  
  var personB = Human()
  personB.firstName = "Andy"
  personB.surName = "-"
  personB.age = 24
  personB.height = 180
  
  print (personB)
  
  if (personA.height &gt; personB.height) { //error here
      print("Person A is taller, he is \(personA.height ?? 1)cms tall")
  } else {
      print("not true")
  }
  </code></pre>
  
  <p>Could anybody explain why I'm receiving the error in simple terms?</p>