Accessing array elements using pointers

we can access the array elements using pointers.

Example

int arr[5] = {100, 200, 300, 400, 500};
int *ptr  = arr;

Where

ptr is an integer pointer which holds the address of the first element. i.e &arr[0]

ptr + 1 points the address of second variable. i.e &arr[1]

Similarly, ptr + 2 holds the address of the third element of the array. i.e. &arr[2]

accessing array using pointer


Printing each array elements address and value

Example

#include<stdio.h>

int main()
{
    int arr[5] = {100, 200, 300, 400, 500}, i;
    int *ptr = arr;

    //Address ptr+i
    //Value stored at the address *(ptr+i)
    for(i = 0; i < 5; i++)
        printf("&arr[%d] = %p\t arr[%d] = %d\n",i,ptr+i,i,*(ptr+i));

    return 0;
}



Modifying array elements using the pointer

Let's change the 3rd (index 2) element as 1000.

Example

#include<stdio.h>

int main()
{
    int arr[5] = {100, 200, 300, 400, 500}, i;
    int *ptr = arr;

    //changing 3rd element(300) as 1000.
    *(ptr+2) = 1000;

    for(i = 0; i < 5; i++)
        printf("arr[%d] = %d\n",i,*(ptr+i));

    return 0;
}