title: Raise/throw exception in SML
body: <p>Write two versions of the function power, the first version takes two integer arguments m and n
  and returns the value m^n</p>
  
  <p>Note that both m and n can be any integers (positive or non-positive).
   The second version of the function is called (cpower m n) and it is the curried version.</p>
  
  <p>Remark: if both m and n are Zero then an exception should be raised. </p>
  
  <pre><code>fun power(m,n) = if n=0 then 1 else m * power(m,n-1);
  
  fun cpower (m,n) : int =
      if n = 0 then 1 else
      if n &gt;= 0 then power(m,n) else
      if n &lt; 0 then 1/power(m,n) else m * cpower (m,n-1);
  </code></pre>
  
  <p><strong>How do I add so that this function throws an exception?</strong></p>