Pointer variable, differences in var and &var

Question

#include <iostream>

using namespace std;

int main() {
    int* z = new int(9);

    cout << "address: " << z << endl;
    cout << "value: " << *z << endl;
    cout << "referance: " << &z << endl;
    return 0;
}

Looking at the cout values, I was expecting the address and reference to give the same address, but heres what the output is:

address: 0x7fc452c032a0
value: 9
referance: 0x7fff5191b8d8

Just curious about the reason for this, is the plain value(z) the address of the variable in the heap with a value of 9, where var(&z) is address of the pointer variable which is located in the stack?

Here is a visualization:

Is the

Answer 1

&z designates the adress of the pointer int * z where you store the allocated adress new int(9).

The pointer z and the value 9 are stored at two different locations in memory.

There is not any notion of reference here, only adresses.

Answer 2

Let me go through some of the basics first.

• A variable is a name that is used to refer to some location in the memory, a location that holds a value with which we are working.

• Using '&' in C/C++ we can get the address of the variable.

• A pointer is a variable that stores the address of a variable. For instance, in the example you are referring to

  int* z = new int(9);
  

  variable z stores the address of the value 9 [new int(9)].

Now, finally this variable has to be stored at some location in the memory and this can be accessed using ampersand (&).

    &z //gives the address of the pointer to value 9 (address of variable z).

This is the same way the pointers and pointers to a pointer (multi level pointers) works.