title: How to do multiple interfaces in Objective C?
body: <p>How can I do the following things in Objective C (the examples below are in pseudo-code):</p>
  
  <ol>
  <li><p>interface A extends B, C</p></li>
  <li><p>interface A</p></li>
  </ol>
  
  <p>interface B</p>
  
  <p>class X inplemements A, B</p>
  
  <p>3.
  interface A</p>
  
  <p>class X implements A</p>
  
  <p>class Y implements A</p>
  
  <p>interface B</p>
  
  <p>class Z extends Y implements B</p>
  
  <p>thanks!</p>