Pointer arithmetic in C++ allows you to perform mathematical operations on pointers. It is mainly used for traversing arrays and working with memory efficiently.

What is Pointer Arithmetic?

Pointer arithmetic means performing operations like increment, decrement, addition, and subtraction on pointers.

Since pointers store memory addresses, these operations move the pointer to different memory locations.

Why Use Pointer Arithmetic?

Pointer arithmetic is useful because it:

Helps traverse arrays efficiently
Provides direct memory access
Improves performance
Is widely used in low-level programming

Basic Pointer Arithmetic Operations

C++ supports the following operations on pointers:

Increment (++)
Decrement (--)
Addition (+)
Subtraction (-)
Difference between pointers

Incrementing a Pointer

Incrementing a pointer moves it to the next memory location of its data type.

#include <iostream>
using namespace std;

int main() {

    int arr[3] = {10, 20, 30};

    int *ptr = arr;

    cout << *ptr << endl;

    ptr++;

    cout << *ptr << endl;

    return 0;
}

Output

10
20

How Increment Works

If an integer takes 4 bytes:

First address → 1000
Next address → 1004
Next address → 1008

The pointer automatically moves according to data type size.

Decrementing a Pointer

ptr--;

This moves the pointer to the previous memory location.

Adding Value to Pointer

ptr = ptr + 2;

This moves the pointer forward by 2 elements.

Example of Addition

#include <iostream>
using namespace std;

int main() {

    int arr[5] = {1, 2, 3, 4, 5};

    int *ptr = arr;

    ptr = ptr + 3;

    cout << *ptr;

    return 0;
}

Output

Subtracting Pointers

You can find the distance between two pointers.

#include <iostream>
using namespace std;

int main() {

    int arr[5] = {10, 20, 30, 40, 50};

    int *ptr1 = &arr[1];
    int *ptr2 = &arr[4];

    cout << ptr2 - ptr1;

    return 0;
}

Output