title: Receiving "Control reaches end of non-void function" error message in Xcode
body: <p>When adding this code to a simple calculator program I receive the error message "Control reaches end of non-void function".</p>
  
  <p>Now after reading some response I know that I should be adding a return call so that the program doesn't hang up in the instance that the accumulator is not set but I want to know where to place it or which would be the proper way to phrase this.</p>
  
  <p>Thanks, any help would be appreciated. I can provide the full program code if necessary as well.</p>
  
  <pre><code>-(double) changeSign
  {
  accumulator = -accumulator;
  }
  
  -(double) reciprocal
  {
  accumulator = 1/accumulator;
  
  }
  
  -(double) xSquared
  {
  accumulator = accumulator * accumulator;
  }
  </code></pre>