//Lori Walker
//cs290, 11-5-95
//In the following program, ATYPE declares an array of nine integers.  Its
//constructor function initialized each member of the array.  The overloaded
//operator[]() fucntion returns the value of the element specified by its
//parameter.

#include <iostream.h> 
#include <stdlib.h> 

const int DEFAULT_SIZE = 9;

class atype  {
  int size;
  int *a; // constructor will allocate storage
public:
  atype(int s0=DEFAULT_SIZE)  {
    size=s0;
    a = new int[s0];
    register int i;
    for(i=0; i<size; i++) a[i] = i;
  }
  int& operator[] (int i)  
  {	if(i>=0 && i<size)return a[i];
	else { cerr<<"Subscript overflow in atype\n"; exit(1); }
  }
  ~atype(){ delete[size] a; }
};

main()
{

  atype ob(11);

  cout << ob[2] << "\n";  	//displays 2
  cout << ob[3] << "\n";	//displays 3
  cout << ob[4] << "\n";	//displays 4
  cout << ob[5] << "\n";	//displays 5

	ob[3] = ob[3]+2;

  cout << ob[2] << "\n";        //displays 2
  cout << ob[3] << "\n";        //displays 5
  cout << ob[4] << "\n";        //displays 4

  ob[10] = 10;	//Should fail

  return 0;
}