Detailed explanation of PHP basic paging class code

class Page

{

public $limit;	//存储limit条件

public $allPage;	//存储总页数

public $current;	//存储当前页

public $total;	//存储总条数

public function __construct($total, $num = 5)

{

//计算总页数

$this->allPage = ceil($total/$num);

//处理当前页

$this->current();

//3,3  6,3

$this->limit = (($this->current-1)*$num).','.$num;

$this->total = $total;

}

protected function current()

{

$p = isset($_GET['p']) ? $_GET['p'] : 1;

// $p = max(1, $p);	//最小不能小于1

// $p = min($p, $this->allPage);//最大不能超过总页数

if ($p < 1) $p = 1;

if ($p > $this->allPage) $p = $this->allPage;

$this->current = (int)$p;

}

public function show()

{

$first = $end = $pre = $next = $_GET;//处理上一页$pre[&#39;p&#39;] = $this->current - 1;

$preStr = http_build_query($pre);

//处理下一页$next[&#39;p&#39;] = $this->current + 1;$nextStr = http_build_query($next);

//处理首页$first[&#39;p&#39;] = 1;

$firstStr = http_build_query($first);

//处理尾页$end[&#39;p&#39;] = $this->allPage;

$endStr = http_build_query($end);

$str = "共{$this->total}条数据 第{$this->current}/{$this->allPage}页 | ";

$str .= "首页| ";$str .= "上一页| ";$str .= "下一页| ";$str .= "尾页";

return $str;

    }

}