title: use a binary tree to encode infix arithmetic expressions on integers
body: <p>This is a question from aws educate. I have been thinking about this for a long time and I am not really getting anywhere.</p>
  
  <blockquote>
    <p>You want to use a binary tree to encode infix arithmetic expressions on integers.  Operations are addition and multiplication
    Draw a picture of what the tree looks like. 
    Write a class definition.
    Write an evaluate() member function.
    How would you make your evaluate() iterative instead of recursive</p>
  </blockquote>
  
  <p>If I could get an explanation that would be fine or some example too</p>