title: how do access previous item in list using linQ?
body: <p>I have:</p>
  
  <pre><code>List&lt;int&gt; A  = new List&lt;int&gt;(){1,2,3,4,5,6};
  
  List&lt;int&gt; m=new List&lt;int&gt;();
  for(int i=1;i&lt;A.count;i++)
  {
  int j=A[i]+A[i-1];
  m.add(j);
  }
  </code></pre>
  
  <p>how can i do this same operation using LinQ?</p>