b

// bai 1
int n, a[100], dem = 0, tong = 0;
cout << "Nhap n: "; cin >> n;
for (int i = 0; i < n; i++) {
  cout << "Nhap a[" << i << "]: "; cin >> a[i];
}
for (int i = 0; i < n; i++) {
  if (a[i] % 2 == 1) dem++;
  if (a[i] >= -20 && a[i] <= 50) tong += a[i];
}
cout << "So luong so le: " << dem << endl;
cout << "Tong trong khoang [-20, 50]: " << tong << endl;

// bai 2
string s; int dem = 0;
cout << "Nhap s: "; getline(cin, s);
for (int i = 0; i < s.size(); i++) {
  if (isupper(s[i])) dem++;
  s[i] = toupper(s[i]);
}
cout << "So ky tu in hoa: " << dem << endl;
cout << "Xau s sau khi chuyen: " << s << endl;