PHP:: three echo statements with the same result
<p>Perhaps this is a petty question, but consider the following PHP code:</p>

<pre><code>$a = "foo1"; $b = "foo2"; $c = "foo3";

echo $a, $b, $c;

echo $a . $b . $c;

echo "$a$b$c";
</code></pre>

<p>aren't these three statements equivalent. What's the difference.
What if one cannot decide whether to use one or the other?</p>
