This example demonstrates another similarity between arrays and pointers. Array elements can be accessed using pointer arithmetic because the array name represents the base address of the array.

#include <stdio.h>

int main()
{
    int a[5] = {10, 20, 30, 40, 50};
    int *ptr;
    int i;

    ptr = a;

    for (i = 0; i < 5; i++)
    {
        printf("%d ", *ptr++);
    }

    printf("\n");

    for (i = 0; i < 5; i++)
    {
        printf("%d ", *(a + i));
    }

    printf("\n");

    return 0;
}

Output:

10 20 30 40 50
10 20 30 40 50

ptr is a pointer variable initialized with the address of the first element of the array.

In the first loop:

• *ptr accesses the current element
• ptr++ moves the pointer to the next integer element

In the second loop:

*(a + i)

accesses array elements using pointer arithmetic.

a + i calculates the address of the ith element from the base address of the array, and * dereferences that address to fetch the value.

This shows that array indexing internally works using pointer arithmetic. For example:

a[i]

is equivalent to:

*(a + i)

The array name behaves like a pointer to the first element, but unlike a normal pointer variable, the array name itself cannot be modified.