title: Set value to computed properties in SWIFT
body: <p>i am trying to learn computed properties in swift..and knew that i need setter to set value for computed properties..i am trying to but stuck..please help me how do i set value in area with setter properties...and would be great if you could tell me how to use setter property and when to use it</p>
  
  <pre><code> class ViewController: UIViewController {
          var width : Int = 20
          var height : Int = 400
          var area: Int{
              get{
                  return width * height
              }set(newarea){
                  area = newarea*10
            //these line gives me an warning and area is not set
              }
          }
  
          override func viewDidLoad() {
              super.viewDidLoad()
              println("\(width)")
              println("\(height)")
              println("\(area)") 
           //  gives an error while setting value to computed properties...       area = 5000
           //  for that we need getter and setter properties in area...
              area = 490
              println("the new area for computed properties is as \(area)")
          }
  </code></pre>
  
  <p>EDIT: however i figured out i can change the other properties of computed properties from which it is derived as </p>
  
  <pre><code>set(newValue){
             // self.area = newValue
              width = newValue/10
              println("the new width for computed properties is as \(width)")
          }
      }
  </code></pre>
  
  <p>But what if i want to change the computed property iteself</p>