<code> ... </code>

<pre> ... </pre>

$('code').replaceWith( "<pre>" + $('code').html() + "</pre>" );

<code> A </code>
<code> B </code>
<code> C </code>

<pre> A </pre>
<pre> A </pre>
<pre> A </pre>

$('code').contents().unwrap().wrap('<pre/>');

$('code').replaceWith(function(){
    return $("<pre />", {html: $(this).html()});
});

$('code').replaceWith(function(){
    return $("<pre />").append($(this).contents());
});

$('code').each(function() {
    $(this).replaceWith( "<pre>" + $(this).html() + "</pre>" );
    // this function is executed for all 'code' elements, and
    // 'this' refers to one element from the set of all 'code'
    // elements each time it is called.
});

$('code').each(function(){

    $(this).replaceWith( "<pre>" + $(this).html() + "</pre>" );

});

$('code').each(function () {
    $(this).replaceWith( "<pre>" + $(this).html() + "</pre>" );
});