#include <iostream>
#include <cstdlib>
#include <cstring>
#include <string>
using namespace std;

template<class T>
class Array {
private:
  int size;
  T *data;

public:
  Array(int s){
    size = s ;
    // data = new T[s];
    data = new T[s];
  }

  T &operator [] (int i) {
    if (i<0 || i >= size) {
      cerr << endl << "Out of range" << endl;
      exit(EXIT_FAILURE);
    }
    else return data[i];
  }

  virtual ~Array() {
    delete[] data;
    cout << "destructor invoke!" << endl;
  }
};

int main() {
  Array<int> arr(5);
  arr[0] = 1;
  arr[1] = arr[0] + 6;

  cout << arr[1] << endl;
  // arr[100] = 3;  // err occur

  Array<string> s(5);
  s[0] = "hello";
  s[1] = "world";

  cout << s[1] << endl;

  return 0;
}