Constructors and Destructors in C++ MCQ question and answer with solution

61.

What will be the output of the following C++ code?

#include <iostream>  
using namespace std;
class A{
	A(){
		cout<<"A's Constructor called\n";
	}
};
class B
{
public:
	A a;
	B(){
		cout<<"B's constructor called\ns";
	}
};
int main(int argc, char const *argv[])
{
	B b;
	return 0;
}

A. A's Constructor called
B's constructor called

B. B's Constructor called
A's constructor called

C. Error

D. Segmentation fault

Answer & Solution Discuss in Board Save for Later

62.
What is a copy constructor?

A. A constructor that allows a user to move data from one object to another

B. A constructor to initialize an object with the values of another object

C. A constructor to check the whether to objects are equal or not

D. A constructor to kill other copies of a given object.

Answer & Solution Discuss in Board Save for Later

63.
When a copy constructor is called?

A. When an object of the class is returned by value

B. When an object of the class is passed by value to a function

C. When an object is constructed based on another object of the same class

D. All of the mentioned

Answer & Solution Discuss in Board Save for Later

64.

Which of the following represents the correct explicit call to a constructor of class A?

class A{
		int a;
	        public:
		A(int i)
                {
			a = i;
		}
       }

A. A a(5);

B. A a;

C. A a = A(5);

D. A a = A();

Answer & Solution Discuss in Board Save for Later

65.

What will be the output of the following C++ code?

#include <iostream>  
using namespace std;
class A{
	~A(){}
};
class B
{
public:
	A a;
};
int main(int argc, char const *argv[])
{
	B b;
	return 0;
}

A. A's Constructor called
B's constructor called

B. B's Constructor called
A's constructor called

C. Error

D. Segmentation fault

Answer & Solution Discuss in Board Save for Later

66.
How many parameters does a default constructor require?

A. 1

B. 2

C. 0

D. 3

Answer & Solution Discuss in Board Save for Later

67.

In the following C++ code how many times the string "A's constructor called" will be printed?

#include <iostream>
#include <string>
using namespace std;
class A{
	int a;
public:
	A(){
		cout<<"A's constructor called";
	}
};
class B{
	static A a;
public:
	B(){
		cout<<"B's constructor called";
	}
	static A get(){
		return a;
	}
};
A B::a;
int main(int argc, char const *argv[])
{
	B b;
	A a1 = b.get();
	A a2 = b.get();
	A a3 = b.get();
}

A. 3

B. 4

C. 2

D. 1

Answer & Solution Discuss in Board Save for Later

68.
What is the role of destructors in Classes?

A. To modify the data whenever required

B. To destroy an object when the lifetime of an object ends

C. To initialize the data members of an object when it is created

D. To call private functions from the outer world

Answer & Solution Discuss in Board Save for Later

69.
What is syntax of defining a destructor of class A?

A. A(){}

B. ~A(){}

C. A::A(){}

D. ~A(){};

Answer & Solution Discuss in Board Save for Later

70.
What happens if a user forgets to define a constructor inside a class?

A. Error occurs

B. Segmentation fault

C. Objects are not created properly

D. Compiler provides a default constructor to avoid faults/errors

Answer & Solution Discuss in Board Save for Later

61.
What will be the output of the following C++ code?

`#include <iostream> using namespace std; class A{ A(){ cout<<"A's Constructor called\n"; } }; class B { public: A a; B(){ cout<<"B's constructor called\ns"; } }; int main(int argc, char const *argv[]) { B b; return 0; }`

Answer & Solution

62.
What is a copy constructor?

Answer & Solution

63.
When a copy constructor is called?

Answer & Solution

64.
Which of the following represents the correct explicit call to a constructor of class A?

`class A{ int a; public: A(int i) { a = i; } }`

Answer & Solution

65.
What will be the output of the following C++ code?

`#include <iostream> using namespace std; class A{ ~A(){} }; class B { public: A a; }; int main(int argc, char const *argv[]) { B b; return 0; }`

Answer & Solution

66.
How many parameters does a default constructor require?

Answer & Solution

Answer & Solution

68.
What is the role of destructors in Classes?

Answer & Solution

69.
What is syntax of defining a destructor of class A?

Answer & Solution

70.
What happens if a user forgets to define a constructor inside a class?

Answer & Solution

Constructors and Destructors in C++ MCQ question and answer with solution | C++ Programimg MCQs

61. What will be the output of the following C++ code? #include <iostream> using namespace std; class A{ A(){ cout<<"A's Constructor called\n"; } }; class B { public: A a; B(){ cout<<"B's constructor called\ns"; } }; int main(int argc, char const *argv[]) { B b; return 0; }

Answer & Solution

62. What is a copy constructor?

Answer & Solution

63. When a copy constructor is called?

Answer & Solution

64. Which of the following represents the correct explicit call to a constructor of class A? class A{ int a; public: A(int i) { a = i; } }

Answer & Solution

65. What will be the output of the following C++ code? #include <iostream> using namespace std; class A{ ~A(){} }; class B { public: A a; }; int main(int argc, char const *argv[]) { B b; return 0; }

Answer & Solution

66. How many parameters does a default constructor require?

Answer & Solution

Answer & Solution

68. What is the role of destructors in Classes?

Answer & Solution

69. What is syntax of defining a destructor of class A?

Answer & Solution

70. What happens if a user forgets to define a constructor inside a class?

Answer & Solution

61.
What will be the output of the following C++ code?

`#include <iostream> using namespace std; class A{ A(){ cout<<"A's Constructor called\n"; } }; class B { public: A a; B(){ cout<<"B's constructor called\ns"; } }; int main(int argc, char const *argv[]) { B b; return 0; }`

62.
What is a copy constructor?

63.
When a copy constructor is called?

64.
Which of the following represents the correct explicit call to a constructor of class A?

`class A{ int a; public: A(int i) { a = i; } }`

65.
What will be the output of the following C++ code?

`#include <iostream> using namespace std; class A{ ~A(){} }; class B { public: A a; }; int main(int argc, char const *argv[]) { B b; return 0; }`

66.
How many parameters does a default constructor require?

68.
What is the role of destructors in Classes?

69.
What is syntax of defining a destructor of class A?

70.
What happens if a user forgets to define a constructor inside a class?