5.5

 1 #include<iostream>
 2 using namespace std;
 3 class Mammal
 4 {
 5 public:
 6     Mammal()
 7     {
 8         cout<<"Mammal constructor...\n";
 9     }
10     ~Mammal()
11     {
12         cout<<"Mammal speak!\n";
13     }
14     virtual void speak()
15     {
16         
17     }
18 };
19 class Dog:public Mammal
20 {
21 public:
22     Dog()
23     {
24         cout<<"Dog Constructor...\n";
25     }
26     ~Dog()
27     {
28         cout<<"Dog destructor...\n";
29     }
30     void speak()
31     {
32         cout<<"Woof\n";
33     } 
34 }; 
35 int main() 
36 {
37     Mammal*pDog=new Dog;
38     pDog->speak();
39     delete pDog;
40     return 0;
41 }