从index.php访问另一个文件

I have problem with access to file. I have folders and files:

public/index.php

app/doit.php

When I use header('Location: ../app/doit.php'); im my index.php, I have error: Object not found!

My site starts with public/index.php

How to have access to doit.php?

header('Location: ../app/doit.php');

it's mean redirect to http://yourhost/public/app/doit.php

to redirect using this code, you must moving app folder to inside public folder

folder structure must be like this public/app/doit.php