#include<iostream>
using namespace std;
void reverse(int arr[], int n, int s, int e) {
    if (s > e) {
        return;
    }
    swap(arr[s], arr[e]);
    s++;
    e--;
    reverse(arr, n, s, e);
    }

     int main() {
         int arr[4] = { 1,2,3,4 };
         int s = 0;
         int e = 3;
         int n = 4;
         reverse(arr, n, s, e);
         for (int i = 0; i < n; i++) {
        cout << arr[i]<<" ";
     }
    }