#include <iostream>
using namespace std;

int main() {
    int n;
    cout << "Enter size of array: ";
    cin >> n;

    int arr[n];
    cout << "Enter " << n << " elements: ";
    for (int i = 0; i < n; i++) {
        cin >> arr[i];
    }

    int sumEven = 0, sumOdd = 0;

    // Traverse array
    for (int i = 0; i < n; i++) {
        if (i % 2 == 0) {
            sumEven += arr[i];   // even index
        } else {
            sumOdd += arr[i];    // odd index
        }
    }

    int difference = sumEven - sumOdd;

    cout << "Sum of even indices = " << sumEven << endl;
    cout << "Sum of odd indices = " << sumOdd << endl;
    cout << "Difference (even - odd) = " << difference << endl;

    return 0;
}