de_4.cpp

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

int main() {
  int n, cnt = 0;
  float a[100], sum = 0, ma = INT_MIN;
  cout << "Nhap n: "; cin >> n;
  for (int i = 0; i < n; i++) {
    cout << "Nhap a[" << i << "]: "; cin >> a[i];
    if (a[i] > 0) {
      sum += a[i]; cnt++;
    }
    if (a[i] < 0) if (ma < a[i]) ma = a[i];
  }
  if (cnt == 0) cout << "Khong co so duong" << endl;
  else cout << "TBC cac so duong: " << sum / cnt << endl;
  if (ma == INT_MIN) cout << "Khong co so am";
  else cout << "So am co GTLN: " << ma;
}