Pointers vs Array in C/C++

An array is the collection of multiple items of the same type stored in contiguous memory locations. While declaring Arrays, the size should be mentioned and their indexing starts from 0 in C/C++.

The position of each element can be calculated by adding an offset to the base value, i.e., the memory location of the first element of the array.

Syntax:

datatype var_name[size_of_array] = {elements};

Example:

C

// C Program to demonstrate the arrays
#include <stdio.h>

int main()
{

    int i, j;

    // Declaring array
    int a[5];

    // Insert elements in array
    for (i = 0; i < 5; i++) {
        a[i] = i + 1;
    }

    // Print elements of array
    for (j = 0; j < 5; j++) {
       printf("%d ",a[j]);
    }
    return 0;
}

C++

// C++ Program to demonstrate the arrays
#include <iostream>
using namespace std;
int main()
{
    int i, j;

    // Declaring array
    int a[5];

    // Insert elements in array
    for (i = 0; i < 5; i++)
    {
        a[i] = i + 1;
    }

    // Print elements of array
    for (j = 0; j < 5; j++)
    {
        cout << a[j] << " ";
    }
    return 0;
}

Output

1 2 3 4 5 

A pointer is the symbolic representation of addresses. It stores the address of variables or memory location. Pointers enable programmers to create and manipulate dynamic data structures. Variables can be of type int, array, char, function, or any other pointer.

Syntax:

datatype *var_name;

Example:

C

// C program to implement Pointers
#include <stdio.h>

int main() {

    int a = 20;

    int* ptr;
    ptr = &a;

      printf("%d  %p  %d ",a,ptr,*ptr);

    return 0;
}

C++

// C++ program to implement Pointers
#include <iostream>
using namespace std;

// Driver code
int main()
{
    int a = 20;
    int* ptr;
    ptr = &a;
    cout << a << " " << ptr <<
            " " << *ptr;
    return 0;
}

Output

20 0x7ffe2ae2d4ec 20

Difference Between Arrays and Pointers in C/C++

The pointer can be used to access the array elements, accessing the whole array using pointer arithmetic, makes the accessing faster. The main difference between Array and Pointers is the fixed size of the memory block. When Arrays are created the fixed size of the memory block is allocated. But with Pointers the memory is dynamically allocated. There are some other differences between an array and a pointer which are discussed below in the table.

S. No.	Array	Pointer
1.	Arrays are declared as type var_name[size];	Pointers are declared as type * var_name;
2.	Collection of elements of similar data type.	Store the address of another variable.
3.	The array can be initialized at the time of definition.	Pointers cannot be initialized at definition.
4.	An array can decide the number of elements it can store.	The pointer can store the address of only one variable.
5.	Arrays are allocated at compile time.	Pointers are allocated at run-time.
6.	Memory allocation is in sequence.	Memory allocation is random.
7.	Arrays are static in nature i.e. they cannot be resized according to the user requirements.	Pointers are dynamic in nature i.e. memory allocated can be resized later.
8.	An array of pointers can be generated.	A pointer to an array can be generated.
9.	Java Support the concept of an array.	Java Does not support pointers.
10.	An array is a group of elements.	Pointer is not a group of elements.