C++ Pointers and Arrays - Simplified Tutorial

Pointers are the variables that store the memory address of another variable. Pointers are used in an array to store the address of the first cell of the array.

int x=10;
// ptr is a pointer storing the address of variable x
int *ptr=&x;

‘&’ operator is used with variable x to return the address of x to ptr

int *ptr;
int arr[5];
ptr=arr;

ptr is the pointer referencing to the first index of the array. Since Array is iterative in nature and elements are stored in a contiguous memory location. So, there is no need to store the address of all other elements separately.

We can replace arr with &arr[0] (i.e. Address of the first element of the array )

int *ptr;
int arr[5];
ptr=&arr[0];

Similarly , for accessing the memory address of other variables of array , we can use &arr[1] , &arr[2], &arr[3] and &arr[4].

Using Dereference operator

int* ptr=arr[0];
*(ptr+1) ⇶ arr[1]
*(ptr+2) ⇶ arr[2]
*(ptr+3) ⇶ arr[3]
*(ptr+4) ⇶ arr[4]

Note – ptr + 1 does not mean that we are shifting 1 byte ahead. It actually means that if we are using an integer type array since the int data type occupies 4 bytes. So, ptr+1 signifies that we are shifting 4 bytes ahead. Similarly, for other data types as well.

Displaying the address of all array elements using array and pointers

Code:

C++ Code

#include <bits/stdc++.h>
using namespace std;
int main()
{
    // Initialising Array
    int arr[5];
 
    // Declaring pointer
    int *ptr;
 
    cout<<"Using array for printing the address of array elements"<<endl;
    for (int i = 0; i < 5; i++)
    {
        cout << "&arr[" << i << "] = " << &arr[i] << endl;
    }
 
    ptr = arr; // or &arr[0] -> address of first element of array
 
    cout<<"Using pointers for printing the address of array elements"<<endl;
    for (int i = 0; i < 5; ++i)
    {
        cout << "ptr + " << i << " = "<< ptr + i << endl;
    }
 
    return 0;
}

Output:

Array name used as a pointer

Code:

C++ Code

#include <bits/stdc++.h>
using namespace std;
int main() {
    int arr[5]={4,5,6,7,8};
 
    // Array name used a pointer
    cout << "Array Elements are: " << endl;
    for (int i = 0; i < 5; ++i) 
    {
        cout << *(arr + i) << endl ;
    }
    return 0;
}

Output:

Special thanks to Gurmeet Singh for contributing to this article on takeUforward. If you also wish to share your knowledge with the takeUforward fam, please check out this article