Derived Classes

1

Which constructor will initialize the base class data member?

A. derived class
B. base class
C. class
D. None of the mentioned

2

Which operator is used to declare the destructor?

A. #
B. ~
C. @
D. $

3

What is the output of this program?

1.
    #include
2.
    using namespace std;
3.
    class X 
4.
    {
5.
        int m;
6.
        public:
7.
        X() : m(10)
8.
        {        
9.
        }
10.
        X(int mm): m(mm)
11.
        {
12.
        }
13.
        int getm()
14.
        {
15.
            return m;
16.
        }
17.
    };
18.
    class Y : public X 
19.
    {
20.
        int n;
21.
        public:
22.
        Y(int nn) : n(nn) {}    
23.
        int getn() { return n; }
24.
    };
25.
    int main()
26.
    {
27.
        Y yobj( 100 );
28.
        cout << yobj.getm() << " " << yobj.getn() << endl;
29.        
    }
A. 10 100
B. 100 10
C. 10 10
D. 100 100

4

What is the output of this program?

1.
    #include 
2.
    using namespace std;
3.
    class Parent
4.
    {
5.
        public:
6.
        Parent (void) 
7.
        {     
8.
            cout << "Parent()\n";
9.
        }
10.
        Parent (int i) 
11.
        { 
12.
            cout << "Parent("<< i << ")\n"; 
13.
        };
14.
        Parent (void) 
15.
        { 
16.
            cout << "~Parent()\n";
17.
        }; 
18.
    };
19.
    class Child1 : public Parent { };
20.
    class Child2 : public Parent
21.
    {
22.
        public:
23.
        Child2 (void) 
24.
        {
25.
            cout << "Child2()\n";
26.
        }
27.
        Child2 (int i) : Parent (i) 
28.
        {
29.
            cout << "Child2(" << i << ")\n"; 
30.
        }
31.
        ~Child2 (void) 
32.
        {
33.
            cout << "~Child2()\n"; 
34.
        }
35.
    };
36.
    int main (void)
37.
    {
38.
        Child1 a;
39.
        Child2 b;
40.
        Child2 c(42);
41.
        return 0;
42.
    }

a) Parent()

Parent()

Child2()

Parent(42)

Child2(42)

~Child2()

~Parent()

~Child2()

~Parent()

~Parent()

b) error

c) runtime error

d) None of the mentioned


5

What is the output of this program?

1.
    #include 
2.
    using namespace std;
3.
    class Base
4.
    {
5.
        public:
6.
        int m;
7.
        Base(int n=0)
8.
        : m(n)
9.
        {
10.
            cout << "Base" << endl;
11.
        }
12.
    };
13.
    class Derived: public Base
14.
    {
15.
        public:
16.
        double d;
17.
        Derived(double de = 0.0)
18.
        : d(de)
19.
        {
20.
            cout << "Derived" << endl;
21.
        }
22.
    };
23.
    int main()
24.
    {
25.
        cout << "Instantiating Base" << endl;
26.
        Base cBase;
27.
        cout << "Instantiating Derived" << endl;
28.
        Derived cDerived;
29.
        return 0;
30.
    }

a) Instantiating Base

Base

Instantiating Derived

Base

Derived

b) Instantiating Base

Instantiating Derived

Base

Derived

c) Instantiating Base

Base

Instantiating Derived

Base

d) None of the mentioned