php 随机数的产生、页面跳转、件读写、文件重命名、switch语句

代码如下：

<?php 
num = rand(1,5); 
witch($num){ 
case 1: 
$fp1=fopen("f1.dat",'r'); 
$oname = fgets($fp1); 
$nname = date("YmdHis"); 

rename($oname,$nname); 
fclose($fp1); 
unlink("f1.dat"); 
$fp1=fopen("f1.dat",'w'); 
fwrite($fp1,$nname); 
fclose($fp1); 

header("Location: ".$nname."/1.html"); 
exit; 
break; 
case 2: 
$fp2=fopen("f2.dat",'r'); 
$oname = fgets($fp2); 

$nname = date("YmdHis"); 
rename($oname,$nname); 
fclose($fp2); 
unlink("f2.dat"); 
$fp2=fopen("f2.dat",'w'); 
fwrite 
($fp2,$nname); 
fclose($fp2); 
header("Location: ".$nname."/2.html"); 
exit; 
break; 
case 3: 
$fp3=fopen 
("f3.dat",'r'); 
$oname = fgets($fp3); 
$nname = date("YmdHis"); 
rename($oname,$nname); 
fclose($fp3); 
unlink 
("f3.dat"); 
$fp3=fopen("f3.dat",'w'); 
fwrite($fp3,$nname); 
fclose($fp3); 
header("Location: ".$nname."/3.html"); 

exit; 
break; 
case 4: 
$fp4=fopen("f4.dat",'r'); 
$oname = fgets($fp4); 
$nname = date("YmdHis"); 
rename 
($oname,$nname); 
fclose($fp4); 
unlink("f4.dat"); 
$fp4=fopen("f4.dat",'w'); 
fwrite($fp4,$nname); 
fclose($fp4); 

header("Location: ".$nname."/4.html"); 
exit; 
break; 
case 5: 
$fp5=fopen("f5.dat",'r'); 
$oname = fgets($fp5); 

$nname = date("YmdHis"); 
rename($oname,$nname); 
fclose($fp5); 
unlink("f5.dat"); 
$fp5=fopen("f5.dat",'w'); 
fwrite 
($fp5,$nname); 
fclose($fp5); 
header("Location: ".$nname."/5.html"); 
exit; 
break; 
default: 
break; 
} 
?>