if post in php code example

Example 1: php if have post

<?php 
if ( have_posts() ) {
	while ( have_posts() ) {
		the_post(); 
		//
		// Post Content here
		//
	} // end while
} // end if
?>

Example 2: php if $_POST

if( isset($_POST['fromPerson']) )
{
     $fromPerson = '+from%3A'.$_POST['fromPerson'];
     echo $fromPerson;
}

//Note: This resolves as true even if all $_POST values are empty strings
if (!empty($_POST))
{
    // handle post data
    $fromPerson = '+from%3A'.$_POST['fromPerson'];
    echo $fromPerson;
}