Arrays and Pointers

In C++, arrays and pointers are closely related, as they both deal with memory addresses. An array is a contiguous block of memory that stores multiple elements of the same data type, while a pointer is a variable that holds the address of another variable or an array element.

Iterating through arrays

In C++, you can iterate through an arbitrary sized array using a for loop:

#include <iostream>

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int size = sizeof(arr) / sizeof(arr[0]); // Calculate the size of the array

    for (int i = 0; i < size; ++i) {
        std::cout << arr[i] << " ";
    }

    return 0;
}

Relationship between Arrays and Pointers

Let's assume we have an integer array arr:

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

The name of the array arr itself points to the base address (i.e., starting address) of the array. This means that you can use a pointer to access the elements of this array.

To understand this better, consider an analogy where each element in the array is a room in a hotel. The hotel represents our memory, and each room (element) has its own unique room number (memory address). The name arr acts like the hotel's entrance - it tells us where the first room starts.

Now let's create an integer pointer p and assign it the base address of our arr.

int* p = arr;

Here, we created a pointer p that points to the first element (room) in our array (hotel). Now we can use this pointer to access individual elements in the array just like using an index

Full Example

#include <iostream>

int main() {
    int  arr[5] = {1, 2, 3, 4, 5};
    int* p = arr;

    std::cout << "First element: " << *p << std::endl;        // Output: First element: 1
    std::cout << "Second element: " << *(p + 1) << std::endl; // Output: Second element: 2

    return 0;
}