Question: How can I hide the user id in the url using php?

I have a button with the user id:

```
<a href="edit.php?id<?php echo $row['user_id']; ?><button>Edit</button></a>

```

How can I hide or better encrypt it?

Answer: 
If it's a vector of standard-library objects, then it is guaranteed to be safe to resize the vector. See [What constitutes a valid state for a "moved from" object in C++11?](https://stackoverflow.com/questions/12095048/what-constitutes-a-valid-state-for-a-moved-from-object-in-c11) .

If a vector of your own objects -- then the question comes back to whether you designed your own objects to be valid once moved from.
```
std::vector<T> v(100, t);
f(std::move(v));
v.resize(120);

```

is similar to your case 1

```
std::vector<T> v(100, t);
f(std::move(v));
g(v);

```

`vector::resize` has no prerequires, but you don't know previous state.
it might be empty, have some size (with unspecified value).

So after `v.resize(120)`, you just know that the new size is `120`, but doesn't know its contents (new elements are default constructed, but which are they?).