Sum of Array Elements Using Pointer Arithmetic in C

Summary: This program calculates the sum of all elements in an array using pointer arithmetic instead of array indexing. It demonstrates pointer traversal over an array using ptr++.

#include <stdio.h>

int main() {
    int arr[100], n, sum = 0;
    int *ptr;

    printf("Enter number of elements: ");
    scanf("%d", &n);

    printf("Enter elements: ");
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    ptr = arr; // pointer points to first element

    for (int i = 0; i < n; i++) {
        sum += *(ptr + i); // pointer arithmetic
    }

    printf("Sum = %d\n", sum);

    return 0;
}

Explanation:

Pointer Traversal:
The pointer ptr is initialized to point to the beginning of the array. Then, *(ptr + i) is used to access each element.

Why Pointer Arithmetic:
Instead of traditional arr[i] indexing, pointer arithmetic gives a deeper understanding of how arrays are laid out in memory.

Memory Efficiency:
This approach doesn't copy or shift any data. It operates directly on memory addresses, making it efficient.

User Interaction:
The user inputs the size and elements of the array, keeping the program interactive and testable with different input sizes.