Algorithmic Computational Models

To get the memory address of the pointer variable itself, you'd take the address of the pointer. In Rust, you can do this by taking a reference to the pointer variable and then converting it to a pointer:

fn main() {
    let x = 42;
    let ptr: *const i32 = &x as *const i32;
    
    // Get the address of the ptr variable itself
    let ptr_to_ptr: *const *const i32 = &ptr as *const *const i32;
    
    println!("Value of x: {}", x);
    println!("Address of x (value of ptr): {:p}", ptr);
    println!("Address of ptr variable itself: {:p}", ptr_to_ptr);
    
    unsafe {
        println!("Dereferencing ptr: {}", *ptr); // Gets 42
        println!("Dereferencing ptr_to_ptr: {:p}", *ptr_to_ptr); // Gets the address of x
    }
}

This creates a pointer to a pointer (double indirection). The type *const *const i32 means "a raw pointer to a raw pointer to an i32".

In memory, this looks like:

1. x (i32): Contains the value 42
2. ptr (*const i32): Contains the address of x
3. ptr_to_ptr (*const *const i32): Contains the address of ptr

This pattern of multiple levels of indirection is commonly used in low-level code, especially when implementing complex data structures or when interfacing with C APIs that use pointers to pointers.