title: Int Variable won't let me add data from UI text field
body: <p>I'm currently working on making a savings app in Xcode 10. I'm working on a feature that lets users add the amount of money they have saved for something into the app through a UI text field. I can't find a way to return the text from the text field to an Integer and add that to the total sum of money that has been saved. Also whenever I tried to add a test variable I got plenty of errors.</p>
  
  <pre><code>var amountSavedSoFar += amountOfMoneySaved
  </code></pre>
  
  <p>Both I have set to be integers. I'm trying to set amountOfMoneySaved equal to the numbers in the text field, but it doesn't seem to work.</p>
  
  <p>'+=' is not a prefix unary operator
  Consecutive statements on a line must be separated by ';'
  Type annotation missing in pattern
  Unary operator cannot be separated from its operand</p>