第三部分：如何实现分页，包括两个函数，两个调用

<?
//分页函数

function genpage(&$sql,$page_size=2)
{
    global $prepage,$nextpage,$pages,$sums;  //out param
    $page = $_GET["page"];
    $eachpage = $page_size;
    $pagesql = strstr($sql," from ");
    $pagesql = "select count(*) as ids ".$pagesql;
    $conn = mysql_query($pagesql) or die(mysql_error());
    if($rs = mysql_fetch_array($conn)) $sums = $rs[0];
    $pages = ceil(($sums-0.5)/$eachpage)-1;
    $pages = $pages>=0?$pages:0;
    $prepage = ($page>0)?$page-1:0;
    $nextpage = ($page<$pages)?$page+1pages;  
    $startpos = $page*$eachpage;
  $sql .=" limit $startpos,$eachpage ";
}
//显示分页
function showpage()
{
  global $page,$pages,$prepage,$nextpage,$queryString; //param from genpage function
  $shownum =10/2;
  $startpage = ($page>=$shownum)?$page-$shownum:0;
  $endpage = ($page+$shownum<=$pages)?$page+$shownumpages;
  
  echo "共".($pages+1)."页: ";
  if($page>0)echo "<a href=$PHP_SELF?page=0$queryString>首页</a>";
  if($startpage>0)
      echo " ... <b><a href=$PHP_SELF?page=".($page-$shownum*2)."$queryString>«</a></b>";
  for($i=$startpage;$i<=$endpage;$i++)
  {
      if($i==$page)  echo " <b>[".($i+1)."]</b> ";
      else      echo " <a href=$PHP_SELF?page=$i$queryString>".($i+1)."</a> ";
  }
  if($endpage<$pages)
      echo "<b><a href=$PHP_SELF?page=".($page+$shownum*2)."$queryString>»</a></b> ... ";
  if($page<$pages)
      echo "<a href=$PHP_SELF?page=$pages$queryString>尾页</a>";

}

//显示带分类的分页
function showpage1()
{
      $fenlei=$_GET["fenleiid"];
  global $page,$pages,$prepage,$nextpage,$queryString; //param from genpage function
  $shownum =10/2;
  $startpage = ($page>=$shownum)?$page-$shownum:0;
  $endpage = ($page+$shownum<=$pages)?$page+$shownumpages;
  
  echo "共".($pages+1)."页: ";
  if($page>0)echo "<a href=$PHP_SELF?fenleiid=$fenlei&page=0$queryString>首页</a>";
  if($startpage>0)
      echo " ... <b><a href=$PHP_SELF?fenleiid=$fenlei&page=".($page-$shownum*2)."$queryString>«</a></b>";
  for($i=$startpage;$i<=$endpage;$i++)
  {
      if($i==$page)  echo " <b>[".($i+1)."]</b> ";
      else      echo " <a href=$PHP_SELF?fenleiid=$fenlei&page=$i$queryString>".($i+1)."</a> ";
  }
  if($endpage<$pages)
      echo "<b><a href=$PHP_SELF?fenleiid=$fenlei&page=".($page+$shownum*2)."$queryString>»</a></b> ... ";
  if($page<$pages)
      echo "<a href=$PHP_SELF?fenleiid=$fenlei&page=$pages$queryString>尾页</a>";

}
?>

<?php
$sql="select * from liuyan order by ly_id desc";
genpage($sql);  //只需要正常代码加上这一行就ok。
$conn=mysql_query($sql,$connec);
while($rs=mysql_fetch_array($conn)){  
?>
<?php
}
?>
<?php  
      showpage(); //显示页
?>
      <?php
      mysql_close();
                      
      ?>