吴裕雄--天生自然PHP-MySQL-JavaScript学习笔记：PHP的结构

<?php
  echo "Hello world";
?>

<?php
/* This is a section
   of multi-line comments
   which will not be
   interpreted */
?>

<?php
  $mycounter = 1;
  $mystring  = "Hello";
  $myarray   = array("One", "Two", "Three");
?>

<?php // test1.php
  $username = "Fred Smith";
  echo $username;
  echo "<br>";
  $current_user = $username;
  echo $current_user;
?>

<?php
  $oxo = array(array('x', ' ', 'o'),
               array('o', 'o', 'x'),
               array('x', 'o', ' '));
  
  echo $oxo[1][2];
?>

<?php
  $author = "Steve Ballmer";

  echo "Developers, Developers, developers, developers, developers,
  developers, developers, developers, developers!

  - $author.";
?>

<?php
  $author = "Bill Gates";

  $text = "Measuring programming progress by lines of code is like
  Measuring aircraft building progress by weight.

  - $author.";
?>

<?php
  $author = "Brian W. Kernighan";

  echo <<<_END
  Debugging is twice as hard as writing the code in the first place.
  Therefore, if you write the code as cleverly as possible, you are,
  by definition, not smart enough to debug it.
  
  - $author.
_END;
?>

<?php
  $author = "Scott Adams";

  $out = <<<_END
  Normal people believe that if it ain’t broke, don’t fix it.
  Engineers believe that if it ain’t broke, it doesn’t have enough
  features yet.

  - $author.
_END;
?>

<?php
  $number = 12345 * 67890;
  echo substr($number, 3, 1);
?>

<?php
  $pi     = "3.1415927";
  $radius = 5;
  echo $pi * ($radius * $radius);
?>

<?php
  function longdate($timestamp)
  {
    return date("l F jS Y", $timestamp);
  }
?>

<?php
  function longdate($timestamp)
  {
    $temp = date("l F jS Y", $timestamp);
    return "The date is $temp";
  }
?>

<?php
  $temp = "The date is ";
  echo longdate(time());

  function longdate($timestamp)
  {
    return $temp . date("l F jS Y", $timestamp);
  }
?>

<?php
  $temp = "The date is ";
  echo $temp . longdate(time());

  function longdate($timestamp)
  {
    return date("l F jS Y", $timestamp);
  }
?>

<?php
  $temp = "The date is ";
  echo longdate($temp, time());

  function longdate($text, $timestamp)
  {
    return $text . date("l F jS Y", $timestamp);
  }
?>

<?php

  echo test();
  echo "<br><br>";
  echo test();
    
  function test()
  {
    static $count = 0;
    echo $count;
    $count++;
  }
?>

<?php
  static $int = 0;         // Allowed 
  static $int = 1+2;       // Disallowed (will produce a Parse error)
  static $int = sqrt(144); // Disallowed
?>