bai_1.cpp

#include <bits/stdc++.h>
using namespace std;

int main() {
  int n, a[100], sum = 0;
  cout << "Nhap n: "; cin >> n;
  for (int i = 0; i < n; i++) {
    cout << "Nhap a[" << i << "] = ";
    cin >> a[i];
    sum += a[i];
  }
  cout << "Tong cac phan tu: " << sum << '\n';
  cout << "Mang a in theo thu tu nguoc lai: ";
  for (int i = n - 1; i >= 0; i--) {
    cout << a[i] << ' ';
  }
  cout << '\n';
  return 0;
}