The & address operator

Learn to take a variable's address with &.

The & address operator

The & address operator gives the memory address of a variable. The syntax: &x. This expression says where x lives in memory. It is often used when assigning to a pointer: int* p = &x;.

The address is a number depending on the variable's type; but printing it directly gives a system-specific format. Assigning the address to a pointer and accessing via *p is safer than dealing with the address directly.

Address and value

A variable has two sides: its value (content) and its address (memory location). x gives the value; &x gives the address. An int* pointer holds the address of an int.

To reach the value through a pointer, use * (dereference): *p gives the value at the address p holds. So after int x = 42; int* p = &x;, *p and x refer to the same value.

Exercise Take an address and access the value

Declare int x = 42;. Assign x's address to p with int* p = &x;. Print the value p points to using *p with std::cout.

Show example solution

#include <iostream>

int main() {
    int x = 42;
    int* p = &x;
    std::cout << *p << "\n";
    return 0;
}

Test yourself

What does this code print?
```
int x = 42;
int* p = &x;
std::cout << *p;
```
- x's address
- 0
- 42
- Error
Show answer

42 — *p gives the value of x, which is 42.

Address operator

int x = 42;
int* p = ____x;

Show answer

int x = 42;
int* p = &x;

Match each expression to its meaning

int* p = &x

Address assignment
&

Address operator
p

Holds the address
*p

Access value

Next lesson: Pointer dereference

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