title: How is a reference different from a pointer in implementation?
body: <blockquote>
  <p><strong>Possible Duplicate:</strong><br />
  <a href="https://stackoverflow.com/questions/57483/difference-between-pointer-variable-and-reference-variable-in-c">Difference between pointer variable and reference variable in C++</a></p>
  </blockquote>
  
  <p>I am reading about the book &quot;Inside the C++ Object Model&quot; by Stanley Lippman. What puzzles me is the difference between a &quot;reference&quot; of an object and a &quot;pointer&quot; to an object. I know that a reference must be initialized when declared, while a pointer could be left for later initialization. But I want to know the physical implementation difference between them.</p>
  <p>Why should there be the &quot;reference&quot; mechanism; isn't it overlapping the function of a pointer? Under what circumstance should we use reference other than pointer?  Many thanks.</p>
  <h2>10:48 AM 11/20/2021</h2>
  <p>Reference is from the semantic perspective.</p>
  <p>Pointer is from the implementation perspective.</p>
  <p>It's kind of like the relation between <em>what</em> and <em>how</em>.</p>