can someone explain why a,*&a and &b outputs the same address

Question

include <iostream>
using namespace std;

int main(){
int *a;
int b=10;
a=&b;

cout<<a<<endl;
cout<<*a<<endl;
cout<<*&a<<endl;
cout<<b<<endl;
cout<<&b<<endl;

return 0;
}

Answer 1

In the code you provided, the a variable is a pointer that stores the address of the b variable. When the cout statements are executed, the following values are output:

a: The address of the b variable is output, because a is a pointer that stores this address.

*a: The value of the b variable is output, because the * operator dereferences the pointer a and accesses the value stored at the address it points to (i.e., the value of b).

*&a: The address of the b variable is output, because the & operator returns the address of a variable, and the * operator dereferences a pointer and accesses the value stored at the address it points to. In this case, *&a returns the address stored in the a pointer, which is the address of the b variable.

b: The value of the b variable is output, because the b variable is not a pointer and its value is accessed directly.

&b: The address of the b variable is output, because the & operator returns the address of a variable.

Answer 2

Hopefully someone with more experience can clarify better, but from what I see:

You created a pointer:

int *a;

then gave var b a value:

int b=10;

then you set 'a' to point at the address of 'b' so 'a' no longer has it's own address, it is pointing at 'b's address (a = address of b):

a=&b;

so essentially the address of a and b are the same. calling a is the same as calling &b:

cout<<a<<endl;

this points to the value of b:

cout<<*a<<endl;

this points to the address of b since you made a=&b:

cout<<*&a<<endl;

this is the value of b:

cout<<b<<endl;

this is the address of b:

cout<<&b<<endl;

Answer 3

A pointer is a type of variable that stores the memory address of another variable. In this code, the pointer a is initialized to point to the memory location of the variable b, so a contains the address of b in memory. The * symbol is used to dereference a pointer, which means to access the value stored at the memory location pointed to by the pointer. Since a points to the same memory location as b, dereferencing a with *a returns the same value as the variable b. *&a also dereferences the pointer a, so it also returns the same value. Since b and &b both represent the same memory location, they both output the same address.

In simpler terms, a, *&a, and &b all represent the same memory location and contain the same value, so they all output the same address.