Item 3:Never treat arrays polymorphically.(More Effective C++)

 1 #include <iostream>
 2 
 3 using namespace std;
 4 
 5 class BST
 6 {
 7 private:
 8     int a;
 9 
10 public:
11     BST(int n) : a(n){};
12     int getData() { return a; }
13     friend ostream& operator<<(ostream &os, BST &bst);
14 };
15 
16 ostream& operator<<(ostream &os, BST &bst)
17 {
18     cout <<  bst.getData();
19     return os;
20 }
21 
22 class BalancedBST : public BST
23 {
24 private:
25     int number;
26 
27 public:
28     BalancedBST(int n1, int n2) : BST(n1), number(n2){}
29 };
30 
31 void print(BST b[], int count)
32 {
33     for(int i=0; i<count; i++)
34     {
35         cout << b[i] << endl;
36     }
37 }
38 
39 int main()
40 {
41     BalancedBST bb1(1,3);
42     BalancedBST bb2(2,4);
43     BalancedBST a[2] = {bb1, bb2};
44     BST b[2] = {bb1, bb2};
45     print(a, 2);
46     print(b, 2);
47 
48     cin.get();
49     return 0;
50 }