Address-Of Operator

Part of the Logic & Flow section of Coddy's C++ journey — lesson 2 of 56.

Now that you understand what a pointer is, you need to learn how to actually get the memory address of a variable. This is where the address-of operator (&) comes in.

The address-of operator & is placed before a variable name to retrieve its memory address. When you use &variable_name, it returns the location in memory where that variable is stored.

int number = 42;
int* ptr = &number;  // ptr now stores the address of number

In this example, &number gets the memory address of the variable number, and we assign that address to our pointer ptr. The pointer doesn't contain the value 42 - it contains the address where 42 is stored.

This connection between a variable and its pointer is essential for working with memory directly. Once you have a pointer storing an address, you can use it to access or modify the original variable indirectly.

Challenge

Easy

Create a program that demonstrates the address-of operator by working with an integer variable and a pointer.

Declare an integer variable named score and initialize it with the value 85.

Create a pointer named scorePtr that stores the memory address of the score variable using the address-of operator.

Print the memory address stored in the pointer using the following format:

Address: [memory address]

The memory address will be displayed in hexadecimal format (like 0x7fff5fbff6ac), which is how C++ typically shows memory addresses.

Cheat sheet

The address-of operator & is used to get the memory address of a variable:

int number = 42;
int* ptr = &number;  // ptr stores the address of number

When you use &variable_name, it returns the location in memory where that variable is stored. The pointer contains the address, not the actual value of the variable.

Try it yourself

#include <iostream>
using namespace std;

int main() {
    // TODO: Write your code below
    
    return 0;
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Logic & Flow

3Project: Task List Tool

Project Overview Adding a Task

Viewing Tasks

Removing a Task

Finishing the Tool

6Sets (Unique Elements)

Introducing std::set Create Set & Add Elements Checking for Elements Removing Elements Iterating Over a Set Recap - Unique Numbers

9Final Challenges

Vector Data Filtering Map Value Search Pointer and Dynamic Array