PHP article paging implementation code

PHP implements paging of article content and automatically paging according to the length of the content. Friends who plan to study this area can refer to it.

The code is as follows:

<?php   
    /*
    * 文章分页
    * bbs.it-home.org
    */  
      
    $fp=fopen('txt.txt','r');  
    while (!feof($fp)){  
         $content.=fgets($fp);   
    }  
    $c_page="";  
    if(isset($_GET['page'])) $c_page=$_GET['page'];   
    $listlen=100;   //分页显示字符数  
    $conlen=strlen($content);   //内容长度  
    $j=0;  
    $listat[0]=0;  
    $lookat=0;  
    for ($i=1;$i<$conlen/$listlen+1;$i++){  
        //echo $conlen/$listlen;  
        if($lookat<$listlen)  
            $lookat=$listlen;  
            if($lookat>$conlen){  
                $j++;  
                $listat[$j]=$conlen;  
                break;  
            }  
        $endat=strpos($content,"\n",$lookat);  
        if($endat>$conlen-$listlen/5 or intval($endat)<1){  
            $j++;  
            $listat[$j]=$conlen;  
            break;  
        }else {  
            $j++;  
            $listat[$j]=$endat;  
            $lookat=$endat+$listlen;  
        }  
              
    }  
    //print page  
    $pagenum=$j;  //总页数  
    $page=intval($c_page);  
    if(emptyempty($page) or $page<1 or $page>$pagenum) $page=1;  
    if($pagenum >1)   
    for ($i=1;$i<$pagenum+1;$i++){  
        echo " {$i} ";  
    }  
    echo "<br>";  
    $stag=$page-1;  
    $startb=$listat[$stag];  
    if($startb>0) //去除首个换行  
    $startb=$startb+1;  
    $cont=substr($content,$startb,$listat[$page]-$startb);  
    echo "<BR/>文章内容：<BR/>";  
    if($page>1)  
    echo "[接上页]       ";  
    echo $cont;      
?>