Php file operations

Php file operation problems & lt ;? Php $ path = & quot; D: \ Install -- Doucment \ wamp \ www \ a.txt & quot; echofilesize ($ path );? & Gt; & nbsp; the following error occurs in the total number of lines of code: Warning: filesi php file operation problem
$ Path = "D: \ Install -- Doucment \ wamp \ www \ a.txt ";

Echo filesize ($ path );
?>

The following error occurs in a total of these lines of code:

Warning: filesize () [function. filesize]: stat failed for D: \ Install -- Doucment \ wamp \ www \ a.txt in D: \ Install -- Doucment \ wamp \ www \ Practice. php on line 4

I cannot find a similar solution on the internet. I don't know which of the following heroes knows the solution... Thank you!

------ Solution --------------------
In PHP, use dirname (_ FILE _). the path should be a backslash (/) rather than a slash \
View http://php.net/manual/zh/function.dirname.php
------ Solution --------------------
There is no other reason for path error. if the file does not exist, this prompt will appear.
You can put the test file and a.txt together to avoid errors.

$ Size = filesize ('./a. php ');
Echo $ size;


------ Solution --------------------
Discussion
$ Path = "D: \ Install -- Doucment \ wamp \ www \ a.txt ";

Echo filesize ($ path );
?>

The following error occurs in a total of these lines of code:

Warning: filesize () [function. filesize]: stat failed for D: \ Install -- Doucment \ wamp \ www \ a.txt ......