title: find middle elements from an array
body: <p>In C++ how can i find the middle 'n' elements of an array? For example if n=3, and the array is [0,1,5,7,7,8,10,14,20], the middle is [7,7,8].</p>
  
  <p>p.s. in my context, n and the elements of array are odd numbers, so i can find the middle.
  Thanks!</p>