title: Barometer Operation in case of Recursive Algorithms
body: <p>I have to find instruction count of Merge Sort using Method called Barometer Operation.</p>
  
  <p><strong>What is Barometer Operation?</strong></p>
  
  <ul>
  <li>A “barometer instruction”  is selected      </li>
  <li>Count = number of times that    barometer instruction is executed.</li>
  <li>Search algorithms:  barometer    instruction (x ==    L[j]?).</li>
  <li>Sort algorithms:  barometer instruction    (L[i] &lt;= L[j]?).</li>
  </ul>
  
  <p>For e.g:-</p>
  
  <pre><code>     for(int i=0;i &lt; n;i++)
         A[i] = i + 1 
  </code></pre>
  
  <p><strong>Barometer operation = +</strong> in body of loop</p>
  
  <p><strong>count(+) = n</strong> </p>
  
  <p>So now problem with Merge Sort is that it is recursive algorithm and I do not know how to choose one particular instruction so that I can count number times that particular instruction is executed.</p>