What kind of array does PHP use?

I can define an array in PHP like this:

$array = array();

In C++, we have two kinds of array.

1. The first kind is a fixed size array, for example:

   int arr[4]; // 4 ints, hardcoded size
   

2. The second kind is a dynamic sized array

   std::vector<int> v; // can grow and shrink at runtime
   

What kind of array does PHP use? Are both kinds of arrays in PHP? If so, can you give me examples?